diff --git a/src/lib/__tests__/date-utils.test.ts b/src/lib/__tests__/date-utils.test.ts
new file mode 100644
index 0000000..fed527d
--- /dev/null
+++ b/src/lib/__tests__/date-utils.test.ts
@@ -0,0 +1,117 @@
+import { describe, it, expect } from 'vitest';
+import { getISOWeek, getWeekYearLabel, getWeekBounds } from '@/lib/date-utils';
+
+// ── getISOWeek ─────────────────────────────────────────────────────────────
+
+describe('getISOWeek', () => {
+  it('returns week 1 for January 4 (always in ISO week 1)', () => {
+    expect(getISOWeek(new Date(2026, 0, 4))).toBe(1);
+    expect(getISOWeek(new Date(2024, 0, 4))).toBe(1);
+  });
+
+  it('returns week 1 for Jan 1 when Jan 1 is Thursday (2026)', () => {
+    // Jan 1, 2026 is a Thursday → week 1
+    expect(getISOWeek(new Date(2026, 0, 1))).toBe(1);
+  });
+
+  it('returns week 53 for Dec 31 when it falls in last ISO week', () => {
+    // Dec 31, 2020 is a Thursday → week 53 of 2020
+    expect(getISOWeek(new Date(2020, 11, 31))).toBe(53);
+  });
+
+  it('returns correct week for a known mid-year date', () => {
+    // Mar 10, 2026 is in week 11
+    expect(getISOWeek(new Date(2026, 2, 10))).toBe(11);
+  });
+
+  it('returns week 52 for Dec 28 (always in ISO week 52 or 53)', () => {
+    // Dec 28 is always in the last week of the year per ISO
+    const week = getISOWeek(new Date(2026, 11, 28));
+    expect(week).toBeGreaterThanOrEqual(52);
+  });
+
+  it('week advances by 1 between consecutive Mondays', () => {
+    const w1 = getISOWeek(new Date(2026, 2, 9));  // Monday March 9
+    const w2 = getISOWeek(new Date(2026, 2, 16)); // Monday March 16
+    expect(w2 - w1).toBe(1);
+  });
+
+  it('same week for all days Monday through Saturday of a given week', () => {
+    // Week of March 9–15, 2026
+    const week = getISOWeek(new Date(2026, 2, 9)); // Monday
+    expect(getISOWeek(new Date(2026, 2, 10))).toBe(week); // Tuesday
+    expect(getISOWeek(new Date(2026, 2, 11))).toBe(week); // Wednesday
+    expect(getISOWeek(new Date(2026, 2, 14))).toBe(week); // Saturday
+  });
+});
+
+// ── getWeekYearLabel ──────────────────────────────────────────────────────
+
+describe('getWeekYearLabel', () => {
+  it('formats as "S{NN}-{YYYY}"', () => {
+    const label = getWeekYearLabel(new Date(2026, 2, 10));
+    expect(label).toMatch(/^S\d{2}-\d{4}$/);
+  });
+
+  it('returns "S11-2026" for March 10 2026', () => {
+    expect(getWeekYearLabel(new Date(2026, 2, 10))).toBe('S11-2026');
+  });
+
+  it('zero-pads single-digit week numbers', () => {
+    // Jan 4, 2026 is week 1
+    expect(getWeekYearLabel(new Date(2026, 0, 4))).toBe('S01-2026');
+  });
+});
+
+// ── getWeekBounds ─────────────────────────────────────────────────────────
+
+describe('getWeekBounds', () => {
+  it('returns Monday as start for a Wednesday', () => {
+    const { start } = getWeekBounds(new Date(2026, 2, 11)); // Wednesday March 11
+    expect(start.getDate()).toBe(9);
+    expect(start.getMonth()).toBe(2); // March
+    expect(start.getFullYear()).toBe(2026);
+  });
+
+  it('returns Sunday as end for a Wednesday', () => {
+    const { end } = getWeekBounds(new Date(2026, 2, 11));
+    expect(end.getDate()).toBe(15);
+    expect(end.getMonth()).toBe(2); // March
+  });
+
+  it('start is at 00:00:00.000', () => {
+    const { start } = getWeekBounds(new Date(2026, 2, 10));
+    expect(start.getHours()).toBe(0);
+    expect(start.getMinutes()).toBe(0);
+    expect(start.getSeconds()).toBe(0);
+    expect(start.getMilliseconds()).toBe(0);
+  });
+
+  it('end is at 23:59:59.999', () => {
+    const { end } = getWeekBounds(new Date(2026, 2, 10));
+    expect(end.getHours()).toBe(23);
+    expect(end.getMinutes()).toBe(59);
+    expect(end.getSeconds()).toBe(59);
+    expect(end.getMilliseconds()).toBe(999);
+  });
+
+  it('start and end are 6 days apart', () => {
+    const { start, end } = getWeekBounds(new Date(2026, 2, 10));
+    const diffDays = (end.getTime() - start.getTime()) / (1000 * 60 * 60 * 24);
+    expect(Math.floor(diffDays)).toBe(6);
+  });
+
+  it('returns same bounds for any day within the same week', () => {
+    const monday = getWeekBounds(new Date(2026, 2, 9));
+    const wednesday = getWeekBounds(new Date(2026, 2, 11));
+    const saturday = getWeekBounds(new Date(2026, 2, 14));
+    expect(monday.start.getTime()).toBe(wednesday.start.getTime());
+    expect(monday.start.getTime()).toBe(saturday.start.getTime());
+    expect(monday.end.getTime()).toBe(wednesday.end.getTime());
+  });
+
+  it('returns Monday as start when given a Monday', () => {
+    const { start } = getWeekBounds(new Date(2026, 2, 9)); // Monday March 9
+    expect(start.getDate()).toBe(9);
+  });
+});
diff --git a/src/lib/__tests__/gravatar.test.ts b/src/lib/__tests__/gravatar.test.ts
new file mode 100644
index 0000000..b23d124
--- /dev/null
+++ b/src/lib/__tests__/gravatar.test.ts
@@ -0,0 +1,57 @@
+import { describe, it, expect } from 'vitest';
+import { getGravatarUrl } from '@/lib/gravatar';
+import { createHash } from 'crypto';
+
+// ── getGravatarUrl ─────────────────────────────────────────────────────────
+
+describe('getGravatarUrl', () => {
+  it('generates a valid gravatar URL', () => {
+    const url = getGravatarUrl('test@example.com');
+    expect(url).toMatch(/^https:\/\/www\.gravatar\.com\/avatar\/[0-9a-f]{32}\?d=identicon&s=\d+$/);
+  });
+
+  it('uses MD5 hash of lowercased/trimmed email', () => {
+    const email = 'Test@Example.COM';
+    const hash = createHash('md5').update(email.toLowerCase().trim()).digest('hex');
+    const url = getGravatarUrl(email);
+    expect(url).toContain(`/avatar/${hash}`);
+  });
+
+  it('produces same URL regardless of email case', () => {
+    const lower = getGravatarUrl('user@example.com');
+    const upper = getGravatarUrl('USER@EXAMPLE.COM');
+    expect(lower).toBe(upper);
+  });
+
+  it('uses default size of 40', () => {
+    const url = getGravatarUrl('test@example.com');
+    expect(url).toContain('s=40');
+  });
+
+  it('uses custom size when provided', () => {
+    const url = getGravatarUrl('test@example.com', 80);
+    expect(url).toContain('s=80');
+  });
+
+  it('uses identicon as default fallback', () => {
+    const url = getGravatarUrl('test@example.com');
+    expect(url).toContain('d=identicon');
+  });
+
+  it('uses custom fallback when provided', () => {
+    const url = getGravatarUrl('test@example.com', 40, 'retro');
+    expect(url).toContain('d=retro');
+  });
+
+  it('produces different hashes for different emails', () => {
+    const url1 = getGravatarUrl('alice@example.com');
+    const url2 = getGravatarUrl('bob@example.com');
+    expect(url1).not.toBe(url2);
+  });
+
+  it('trims whitespace from email before hashing', () => {
+    const trimmed = getGravatarUrl('user@example.com');
+    const padded = getGravatarUrl('  user@example.com  ');
+    expect(trimmed).toBe(padded);
+  });
+});
diff --git a/src/lib/__tests__/okr-utils.test.ts b/src/lib/__tests__/okr-utils.test.ts
new file mode 100644
index 0000000..c788994
--- /dev/null
+++ b/src/lib/__tests__/okr-utils.test.ts
@@ -0,0 +1,105 @@
+import { describe, it, expect } from 'vitest';
+import { getCurrentQuarterPeriod, isCurrentQuarterPeriod, comparePeriods } from '@/lib/okr-utils';
+
+// ── getCurrentQuarterPeriod ────────────────────────────────────────────────
+
+describe('getCurrentQuarterPeriod', () => {
+  it('returns Q1 for January', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 0, 15))).toBe('Q1 2026');
+  });
+
+  it('returns Q1 for March', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 2, 31))).toBe('Q1 2026');
+  });
+
+  it('returns Q2 for April', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 3, 1))).toBe('Q2 2026');
+  });
+
+  it('returns Q2 for June', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 5, 30))).toBe('Q2 2026');
+  });
+
+  it('returns Q3 for July', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 6, 1))).toBe('Q3 2026');
+  });
+
+  it('returns Q4 for October', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 9, 1))).toBe('Q4 2026');
+  });
+
+  it('returns Q4 for December', () => {
+    expect(getCurrentQuarterPeriod(new Date(2026, 11, 31))).toBe('Q4 2026');
+  });
+
+  it('includes the correct year', () => {
+    expect(getCurrentQuarterPeriod(new Date(2025, 0, 1))).toBe('Q1 2025');
+    expect(getCurrentQuarterPeriod(new Date(2027, 6, 1))).toBe('Q3 2027');
+  });
+});
+
+// ── isCurrentQuarterPeriod ─────────────────────────────────────────────────
+
+describe('isCurrentQuarterPeriod', () => {
+  it('returns true for matching period and date', () => {
+    expect(isCurrentQuarterPeriod('Q1 2026', new Date(2026, 1, 15))).toBe(true);
+  });
+
+  it('returns false for different quarter', () => {
+    expect(isCurrentQuarterPeriod('Q2 2026', new Date(2026, 0, 15))).toBe(false);
+  });
+
+  it('returns false for different year', () => {
+    expect(isCurrentQuarterPeriod('Q1 2025', new Date(2026, 0, 15))).toBe(false);
+  });
+
+  it('returns false for empty string', () => {
+    expect(isCurrentQuarterPeriod('', new Date(2026, 0, 15))).toBe(false);
+  });
+});
+
+// ── comparePeriods ─────────────────────────────────────────────────────────
+
+describe('comparePeriods', () => {
+  it('returns 0 for identical periods', () => {
+    expect(comparePeriods('Q1 2026', 'Q1 2026')).toBe(0);
+  });
+
+  it('returns negative when a is more recent than b (a should sort first)', () => {
+    // Q2 2026 is more recent than Q1 2026
+    expect(comparePeriods('Q2 2026', 'Q1 2026')).toBeLessThan(0);
+  });
+
+  it('returns positive when a is older than b (a should sort after)', () => {
+    expect(comparePeriods('Q1 2026', 'Q2 2026')).toBeGreaterThan(0);
+  });
+
+  it('sorts by year before quarter', () => {
+    // Q4 2025 is older than Q1 2026
+    expect(comparePeriods('Q4 2025', 'Q1 2026')).toBeGreaterThan(0);
+    expect(comparePeriods('Q1 2026', 'Q4 2025')).toBeLessThan(0);
+  });
+
+  it('handles same year, different quarters correctly', () => {
+    expect(comparePeriods('Q4 2026', 'Q1 2026')).toBeLessThan(0);
+    expect(comparePeriods('Q1 2026', 'Q4 2026')).toBeGreaterThan(0);
+  });
+
+  it('puts parseable period before unparseable one', () => {
+    // 'Q1 2026' can be parsed, 'custom period' cannot
+    expect(comparePeriods('Q1 2026', 'custom period')).toBeLessThan(0);
+    expect(comparePeriods('custom period', 'Q1 2026')).toBeGreaterThan(0);
+  });
+
+  it('falls back to string comparison when neither is parseable', () => {
+    const result = comparePeriods('beta', 'alpha');
+    // String descending: 'beta' > 'alpha' → b.localeCompare(a) = 'alpha'.localeCompare('beta') < 0
+    expect(result).toBeLessThan(0);
+  });
+
+  it('produces correct sort order for a mixed list', () => {
+    const periods = ['Q1 2025', 'Q4 2026', 'Q2 2026', 'Q1 2026'];
+    const sorted = [...periods].sort(comparePeriods);
+    expect(sorted).toEqual(['Q4 2026', 'Q2 2026', 'Q1 2026', 'Q1 2025']);
+  });
+});
diff --git a/src/lib/__tests__/share-utils.test.ts b/src/lib/__tests__/share-utils.test.ts
new file mode 100644
index 0000000..5230266
--- /dev/null
+++ b/src/lib/__tests__/share-utils.test.ts
@@ -0,0 +1,69 @@
+import { describe, it, expect } from 'vitest';
+import { getTeamMembersForShare } from '@/lib/share-utils';
+
+const alice = { id: 'u1', email: 'alice@ex.com', name: 'Alice' };
+const bob = { id: 'u2', email: 'bob@ex.com', name: 'Bob' };
+const charlie = { id: 'u3', email: 'charlie@ex.com', name: 'Charlie' };
+
+// ── getTeamMembersForShare ─────────────────────────────────────────────────
+
+describe('getTeamMembersForShare', () => {
+  it('returns empty array when teams have no members', () => {
+    const result = getTeamMembersForShare([{ id: 't1', name: 'Team', description: null, members: [] }], 'u1');
+    expect(result).toEqual([]);
+  });
+
+  it('returns empty array when all members are the current user', () => {
+    const teams = [{ id: 't1', name: 'Team', description: null, members: [{ user: alice }] }];
+    const result = getTeamMembersForShare(teams, alice.id);
+    expect(result).toEqual([]);
+  });
+
+  it('excludes the current user from results', () => {
+    const teams = [{ id: 't1', name: 'Team', description: null, members: [{ user: alice }, { user: bob }] }];
+    const result = getTeamMembersForShare(teams, alice.id);
+    expect(result).toHaveLength(1);
+    expect(result[0].id).toBe(bob.id);
+  });
+
+  it('deduplicates users appearing in multiple teams', () => {
+    const teams = [
+      { id: 't1', name: 'Team A', description: null, members: [{ user: bob }, { user: charlie }] },
+      { id: 't2', name: 'Team B', description: null, members: [{ user: bob }] }, // bob repeated
+    ];
+    const result = getTeamMembersForShare(teams, alice.id);
+    const ids = result.map((u) => u.id);
+    expect(ids).toContain(bob.id);
+    expect(ids).toContain(charlie.id);
+    expect(ids.filter((id) => id === bob.id)).toHaveLength(1); // no duplicate
+  });
+
+  it('returns all unique members across teams excluding current user', () => {
+    const teams = [
+      { id: 't1', name: 'T1', description: null, members: [{ user: alice }, { user: bob }] },
+      { id: 't2', name: 'T2', description: null, members: [{ user: charlie }] },
+    ];
+    const result = getTeamMembersForShare(teams, alice.id);
+    const ids = result.map((u) => u.id);
+    expect(ids).not.toContain(alice.id);
+    expect(ids).toContain(bob.id);
+    expect(ids).toContain(charlie.id);
+    expect(result).toHaveLength(2);
+  });
+
+  it('handles teams without members property (undefined)', () => {
+    const teams = [{ id: 't1', name: 'Team', description: null }]; // no members key
+    const result = getTeamMembersForShare(teams, alice.id);
+    expect(result).toEqual([]);
+  });
+
+  it('returns empty array when no teams provided', () => {
+    expect(getTeamMembersForShare([], 'u1')).toEqual([]);
+  });
+
+  it('preserves user fields (id, email, name)', () => {
+    const teams = [{ id: 't1', name: 'T', description: null, members: [{ user: bob }] }];
+    const result = getTeamMembersForShare(teams, alice.id);
+    expect(result[0]).toEqual(bob);
+  });
+});
diff --git a/src/lib/__tests__/weather-utils.test.ts b/src/lib/__tests__/weather-utils.test.ts
new file mode 100644
index 0000000..7a69749
--- /dev/null
+++ b/src/lib/__tests__/weather-utils.test.ts
@@ -0,0 +1,117 @@
+import { describe, it, expect } from 'vitest';
+import { getEmojiScore, getAverageEmoji, getEmojiEvolution, WEATHER_EMOJIS } from '@/lib/weather-utils';
+
+// ── getEmojiScore ─────────────────────────────────────────────────────────
+
+describe('getEmojiScore', () => {
+  it('returns null for null', () => {
+    expect(getEmojiScore(null)).toBeNull();
+  });
+
+  it('returns null for undefined', () => {
+    expect(getEmojiScore(undefined)).toBeNull();
+  });
+
+  it('returns null for empty string (Aucun = index 0)', () => {
+    expect(getEmojiScore('')).toBeNull();
+  });
+
+  it('returns null for unknown emoji', () => {
+    expect(getEmojiScore('🦄')).toBeNull();
+  });
+
+  it('returns 1 for ☀️ (first scored emoji)', () => {
+    expect(getEmojiScore('☀️')).toBe(1);
+  });
+
+  it('returns 19 for ✨ (last emoji in list)', () => {
+    expect(getEmojiScore('✨')).toBe(19);
+  });
+
+  it('returns consistent 1-based index for all emojis in WEATHER_EMOJIS', () => {
+    for (let i = 1; i < WEATHER_EMOJIS.length; i++) {
+      expect(getEmojiScore(WEATHER_EMOJIS[i].emoji)).toBe(i);
+    }
+  });
+});
+
+// ── getAverageEmoji ───────────────────────────────────────────────────────
+
+describe('getAverageEmoji', () => {
+  it('returns null for empty array', () => {
+    expect(getAverageEmoji([])).toBeNull();
+  });
+
+  it('returns null when all values are null/undefined', () => {
+    expect(getAverageEmoji([null, undefined, null])).toBeNull();
+  });
+
+  it('returns null when all emojis are unknown (score null)', () => {
+    expect(getAverageEmoji(['🦄', '🤖'])).toBeNull();
+  });
+
+  it('returns the same emoji when only one is provided', () => {
+    expect(getAverageEmoji(['☀️'])).toBe('☀️');
+  });
+
+  it('ignores null values and uses only scored emojis', () => {
+    // Only ☀️ (1) is valid
+    expect(getAverageEmoji([null, '☀️', null])).toBe('☀️');
+  });
+
+  it('returns emoji closest to the average score', () => {
+    // ☀️ = 1, ☁️ = 4 → avg = 2.5 → closest is 🌤️(2) or ⛅(3), both at dist 0.5
+    // Code picks 🌤️ (lower index wins on tie)
+    const result = getAverageEmoji(['☀️', '☁️']);
+    expect(['🌤️', '⛅']).toContain(result);
+  });
+
+  it('returns exact match when average is a whole number score', () => {
+    // ☀️ = 1, 🌤️ = 2 → avg = 1.5 → dist(☀️)=0.5, dist(🌤️)=0.5 → ☀️ wins (lower index)
+    expect(getAverageEmoji(['☀️', '🌤️'])).toBe('☀️');
+  });
+});
+
+// ── getEmojiEvolution ─────────────────────────────────────────────────────
+
+describe('getEmojiEvolution', () => {
+  it('returns null when current is null', () => {
+    expect(getEmojiEvolution(null, '☀️')).toBeNull();
+  });
+
+  it('returns null when previous is null', () => {
+    expect(getEmojiEvolution('☀️', null)).toBeNull();
+  });
+
+  it('returns null when both are null', () => {
+    expect(getEmojiEvolution(null, null)).toBeNull();
+  });
+
+  it('returns null when current is unknown emoji', () => {
+    expect(getEmojiEvolution('🦄', '☀️')).toBeNull();
+  });
+
+  it('returns null when previous is unknown emoji', () => {
+    expect(getEmojiEvolution('☀️', '🦄')).toBeNull();
+  });
+
+  it('returns "same" when both emojis are identical', () => {
+    expect(getEmojiEvolution('☀️', '☀️')).toBe('same');
+  });
+
+  it('returns "up" when current score is lower (better weather)', () => {
+    // ☀️ = 1 (better), 🌧️ = 6 (worse)
+    // going from 🌧️ to ☀️: delta = 1 - 6 = -5 → "up"
+    expect(getEmojiEvolution('☀️', '🌧️')).toBe('up');
+  });
+
+  it('returns "down" when current score is higher (worse weather)', () => {
+    // going from ☀️ to 🌧️: delta = 6 - 1 = 5 → "down"
+    expect(getEmojiEvolution('🌧️', '☀️')).toBe('down');
+  });
+
+  it('handles adjacent emojis', () => {
+    // ☀️(1) → 🌤️(2): delta = 2-1 = 1 → "down" (slight degradation)
+    expect(getEmojiEvolution('🌤️', '☀️')).toBe('down');
+  });
+});
diff --git a/src/lib/__tests__/workshops.test.ts b/src/lib/__tests__/workshops.test.ts
new file mode 100644
index 0000000..d7f122e
--- /dev/null
+++ b/src/lib/__tests__/workshops.test.ts
@@ -0,0 +1,140 @@
+import { describe, it, expect } from 'vitest';
+import {
+  WORKSHOPS,
+  WORKSHOP_BY_ID,
+  WORKSHOP_TYPE_IDS,
+  VALID_TAB_PARAMS,
+  getWorkshop,
+  getSessionPath,
+  getSessionsTabUrl,
+  withWorkshopType,
+} from '@/lib/workshops';
+
+// ── Registry integrity ─────────────────────────────────────────────────────
+
+describe('WORKSHOPS registry', () => {
+  it('contains exactly 6 workshop types', () => {
+    expect(WORKSHOPS).toHaveLength(6);
+  });
+
+  it('all workshop IDs match WORKSHOP_TYPE_IDS', () => {
+    const ids = WORKSHOPS.map((w) => w.id);
+    expect(ids).toEqual([...WORKSHOP_TYPE_IDS]);
+  });
+
+  it('every workshop has required fields', () => {
+    for (const w of WORKSHOPS) {
+      expect(w.id).toBeTruthy();
+      expect(w.path).toMatch(/^\//);
+      expect(w.newPath).toMatch(/^\//);
+      expect(w.label).toBeTruthy();
+      expect(w.icon).toBeTruthy();
+    }
+  });
+
+  it('workshops with participant have non-empty participantLabel', () => {
+    for (const w of WORKSHOPS) {
+      if (w.hasParticipant) {
+        expect(w.participantLabel).toBeTruthy();
+      } else {
+        expect(w.participantLabel).toBe('');
+      }
+    }
+  });
+
+  it('every workshop has home content with at least 1 feature', () => {
+    for (const w of WORKSHOPS) {
+      expect(w.home.tagline).toBeTruthy();
+      expect(w.home.description).toBeTruthy();
+      expect(w.home.features.length).toBeGreaterThanOrEqual(1);
+    }
+  });
+});
+
+describe('WORKSHOP_BY_ID', () => {
+  it('contains an entry for every workshop type', () => {
+    for (const id of WORKSHOP_TYPE_IDS) {
+      expect(WORKSHOP_BY_ID[id]).toBeDefined();
+      expect(WORKSHOP_BY_ID[id].id).toBe(id);
+    }
+  });
+});
+
+describe('VALID_TAB_PARAMS', () => {
+  it('includes all workshop IDs plus "all", "byPerson", "team"', () => {
+    expect(VALID_TAB_PARAMS).toContain('all');
+    expect(VALID_TAB_PARAMS).toContain('byPerson');
+    expect(VALID_TAB_PARAMS).toContain('team');
+    for (const id of WORKSHOP_TYPE_IDS) {
+      expect(VALID_TAB_PARAMS).toContain(id);
+    }
+  });
+});
+
+// ── getWorkshop ────────────────────────────────────────────────────────────
+
+describe('getWorkshop', () => {
+  it('returns the correct workshop config', () => {
+    const swot = getWorkshop('swot');
+    expect(swot.id).toBe('swot');
+    expect(swot.path).toBe('/sessions');
+  });
+
+  it('returns different configs for different IDs', () => {
+    expect(getWorkshop('swot').path).not.toBe(getWorkshop('motivators').path);
+  });
+});
+
+// ── getSessionPath ─────────────────────────────────────────────────────────
+
+describe('getSessionPath', () => {
+  it('builds path for swot', () => {
+    expect(getSessionPath('swot', 'abc123')).toBe('/sessions/abc123');
+  });
+
+  it('builds path for motivators', () => {
+    expect(getSessionPath('motivators', 'xyz')).toBe('/motivators/xyz');
+  });
+
+  it('builds path for weather', () => {
+    expect(getSessionPath('weather', 'w-1')).toBe('/weather/w-1');
+  });
+});
+
+// ── getSessionsTabUrl ──────────────────────────────────────────────────────
+
+describe('getSessionsTabUrl', () => {
+  it('generates correct tab URL', () => {
+    expect(getSessionsTabUrl('swot')).toBe('/sessions?tab=swot');
+    expect(getSessionsTabUrl('motivators')).toBe('/sessions?tab=motivators');
+    expect(getSessionsTabUrl('weather')).toBe('/sessions?tab=weather');
+  });
+});
+
+// ── withWorkshopType ───────────────────────────────────────────────────────
+
+describe('withWorkshopType', () => {
+  it('adds workshopType to each item', () => {
+    const sessions = [{ id: 'a' }, { id: 'b' }];
+    const result = withWorkshopType(sessions, 'swot');
+    expect(result[0]).toEqual({ id: 'a', workshopType: 'swot' });
+    expect(result[1]).toEqual({ id: 'b', workshopType: 'swot' });
+  });
+
+  it('returns empty array for empty input', () => {
+    expect(withWorkshopType([], 'motivators')).toEqual([]);
+  });
+
+  it('preserves all original properties', () => {
+    const sessions = [{ id: 'x', title: 'Test', createdAt: new Date() }];
+    const result = withWorkshopType(sessions, 'year-review');
+    expect(result[0].title).toBe('Test');
+    expect(result[0].workshopType).toBe('year-review');
+  });
+
+  it('does not mutate the original array', () => {
+    const sessions = [{ id: 'a' }];
+    withWorkshopType(sessions, 'swot');
+    expect(sessions[0]).not.toHaveProperty('workshopType');
+  });
+});
diff --git a/src/services/__tests__/auth.test.ts b/src/services/__tests__/auth.test.ts
new file mode 100644
index 0000000..285c5de
--- /dev/null
+++ b/src/services/__tests__/auth.test.ts
@@ -0,0 +1,290 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import {
+  batchResolveCollaborators,
+  resolveCollaborator,
+  registerUser,
+  updateUserPassword,
+  updateUserProfile,
+} from '@/services/auth';
+
+vi.mock('@/services/database', () => ({
+  prisma: {
+    user: {
+      findMany: vi.fn(),
+      findUnique: vi.fn(),
+      findFirst: vi.fn(),
+      create: vi.fn(),
+      update: vi.fn(),
+    },
+  },
+}));
+
+vi.mock('bcryptjs', () => ({
+  hash: vi.fn().mockResolvedValue('hashed_password'),
+  compare: vi.fn(),
+}));
+
+// Import after mock to get the mocked version
+const { prisma } = await import('@/services/database');
+const mockFindMany = vi.mocked(prisma.user.findMany);
+const mockFindUnique = vi.mocked(prisma.user.findUnique);
+const mockFindFirst = vi.mocked(prisma.user.findFirst);
+const mockCreate = vi.mocked(prisma.user.create);
+const mockUpdate = vi.mocked(prisma.user.update);
+
+const { hash: mockHash, compare: mockCompare } = await import('bcryptjs');
+const mockHashFn = vi.mocked(mockHash);
+const mockCompareFn = vi.mocked(mockCompare);
+
+const alice = { id: 'u1', email: 'alice@example.com', name: 'Alice' };
+const bob = { id: 'u2', email: 'bob@example.com', name: 'Bob' };
+
+// ── batchResolveCollaborators ──────────────────────────────────────────────
+
+describe('batchResolveCollaborators', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns empty map for empty input without DB calls', async () => {
+    const result = await batchResolveCollaborators([]);
+    expect(result.size).toBe(0);
+    expect(mockFindMany).not.toHaveBeenCalled();
+  });
+
+  it('resolves an email to its user', async () => {
+    mockFindMany.mockResolvedValueOnce([alice]); // email query
+    const result = await batchResolveCollaborators(['alice@example.com']);
+    expect(result.get('alice@example.com')).toEqual({ raw: 'alice@example.com', matchedUser: alice });
+  });
+
+  it('email matching is case-insensitive', async () => {
+    mockFindMany.mockResolvedValueOnce([alice]); // DB returns lowercase email
+    const result = await batchResolveCollaborators(['Alice@Example.COM']);
+    expect(result.get('Alice@Example.COM')?.matchedUser).toEqual(alice);
+  });
+
+  it('resolves a name to its user', async () => {
+    mockFindMany.mockResolvedValueOnce([bob]); // name query (no emails → 1 call)
+    const result = await batchResolveCollaborators(['Bob']);
+    expect(result.get('Bob')).toEqual({ raw: 'Bob', matchedUser: bob });
+  });
+
+  it('name matching is case-insensitive', async () => {
+    mockFindMany.mockResolvedValueOnce([bob]);
+    const result = await batchResolveCollaborators(['BOB']);
+    expect(result.get('BOB')?.matchedUser).toEqual(bob);
+  });
+
+  it('returns null matchedUser when email not found', async () => {
+    mockFindMany.mockResolvedValueOnce([]); // no match
+    const result = await batchResolveCollaborators(['nobody@example.com']);
+    expect(result.get('nobody@example.com')).toEqual({ raw: 'nobody@example.com', matchedUser: null });
+  });
+
+  it('returns null matchedUser when name not found', async () => {
+    mockFindMany.mockResolvedValueOnce([]);
+    const result = await batchResolveCollaborators(['Unknown']);
+    expect(result.get('Unknown')).toEqual({ raw: 'Unknown', matchedUser: null });
+  });
+
+  it('handles mixed emails and names in exactly 2 DB queries', async () => {
+    mockFindMany
+      .mockResolvedValueOnce([alice]) // email query
+      .mockResolvedValueOnce([bob]);  // name query
+    const result = await batchResolveCollaborators(['alice@example.com', 'Bob']);
+    expect(mockFindMany).toHaveBeenCalledTimes(2);
+    expect(result.get('alice@example.com')?.matchedUser).toEqual(alice);
+    expect(result.get('Bob')?.matchedUser).toEqual(bob);
+  });
+
+  it('deduplicates identical inputs (only 1 DB entry per unique value)', async () => {
+    mockFindMany.mockResolvedValueOnce([alice]); // only emails → 1 call
+    const result = await batchResolveCollaborators(['alice@example.com', 'alice@example.com']);
+    expect(mockFindMany).toHaveBeenCalledTimes(1);
+    expect(result.size).toBe(1);
+  });
+
+  it('skips email query when no emails present', async () => {
+    mockFindMany.mockResolvedValueOnce([bob]);
+    await batchResolveCollaborators(['Bob']);
+    expect(mockFindMany).toHaveBeenCalledTimes(1);
+    expect(mockFindMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: expect.objectContaining({ OR: expect.any(Array) }) })
+    );
+  });
+
+  it('skips name query when no names present', async () => {
+    mockFindMany.mockResolvedValueOnce([alice]);
+    await batchResolveCollaborators(['alice@example.com']);
+    expect(mockFindMany).toHaveBeenCalledTimes(1);
+    expect(mockFindMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: expect.objectContaining({ email: expect.any(Object) }) })
+    );
+  });
+
+  it('handles whitespace-padded inputs', async () => {
+    mockFindMany.mockResolvedValueOnce([alice]);
+    const result = await batchResolveCollaborators(['  alice@example.com  ']);
+    expect(result.get('alice@example.com')?.matchedUser).toEqual(alice);
+  });
+
+  it('resolves multiple unique names in one query', async () => {
+    const charlie = { id: 'u3', email: 'c@example.com', name: 'Charlie' };
+    mockFindMany.mockResolvedValueOnce([bob, charlie]);
+    const result = await batchResolveCollaborators(['Bob', 'Charlie']);
+    expect(mockFindMany).toHaveBeenCalledTimes(1);
+    expect(result.get('Bob')?.matchedUser).toEqual(bob);
+    expect(result.get('Charlie')?.matchedUser).toEqual(charlie);
+  });
+});
+
+// ── resolveCollaborator ────────────────────────────────────────────────────
+
+describe('resolveCollaborator', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('resolves email via findUnique', async () => {
+    mockFindUnique.mockResolvedValueOnce(alice);
+    const result = await resolveCollaborator('alice@example.com');
+    expect(result).toEqual({ raw: 'alice@example.com', matchedUser: alice });
+    expect(mockFindUnique).toHaveBeenCalledWith({ where: { email: 'alice@example.com' }, select: expect.any(Object) });
+  });
+
+  it('returns null matchedUser when email not found', async () => {
+    mockFindUnique.mockResolvedValueOnce(null);
+    const result = await resolveCollaborator('ghost@example.com');
+    expect(result.matchedUser).toBeNull();
+  });
+
+  it('resolves name via findFirst when not an email', async () => {
+    mockFindFirst.mockResolvedValueOnce(bob);
+    const result = await resolveCollaborator('Bob');
+    expect(result.matchedUser).toEqual(bob);
+  });
+
+  it('returns null matchedUser when name not found', async () => {
+    mockFindFirst.mockResolvedValueOnce(null);
+    const result = await resolveCollaborator('Nobody');
+    expect(result.matchedUser).toBeNull();
+  });
+
+  it('rejects partial name matches (contains but not exact)', async () => {
+    // findFirst returns a user whose name doesn't match exactly
+    mockFindFirst.mockResolvedValueOnce({ id: 'u1', email: 'a@ex.com', name: 'Bobby' });
+    const result = await resolveCollaborator('Bob');
+    expect(result.matchedUser).toBeNull();
+  });
+});
+
+// ── registerUser ──────────────────────────────────────────────────────────
+
+describe('registerUser', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns error when email already exists', async () => {
+    mockFindUnique.mockResolvedValueOnce(alice);
+    const result = await registerUser({ email: 'alice@example.com', password: 'secret' });
+    expect(result.success).toBe(false);
+    expect(result.error).toMatch(/existe déjà/);
+    expect(mockCreate).not.toHaveBeenCalled();
+  });
+
+  it('hashes password and creates user on success', async () => {
+    mockFindUnique.mockResolvedValueOnce(null);
+    mockCreate.mockResolvedValueOnce({ id: 'new-id', email: 'new@example.com', name: null });
+    const result = await registerUser({ email: 'new@example.com', password: 'secret' });
+    expect(mockHashFn).toHaveBeenCalledWith('secret', 12);
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ email: 'new@example.com', password: 'hashed_password' }) })
+    );
+    expect(result.success).toBe(true);
+    expect(result.user?.email).toBe('new@example.com');
+  });
+
+  it('returns only id, email, name fields', async () => {
+    mockFindUnique.mockResolvedValueOnce(null);
+    mockCreate.mockResolvedValueOnce({ id: 'x', email: 'x@ex.com', name: 'X' });
+    const result = await registerUser({ email: 'x@ex.com', password: 'p', name: 'X' });
+    expect(result.user).toEqual({ id: 'x', email: 'x@ex.com', name: 'X' });
+  });
+
+  it('sets name to null when not provided', async () => {
+    mockFindUnique.mockResolvedValueOnce(null);
+    mockCreate.mockResolvedValueOnce({ id: 'y', email: 'y@ex.com', name: null });
+    await registerUser({ email: 'y@ex.com', password: 'p' });
+    expect(mockCreate).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ name: null }) })
+    );
+  });
+});
+
+// ── updateUserPassword ────────────────────────────────────────────────────
+
+describe('updateUserPassword', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns error when user not found', async () => {
+    mockFindUnique.mockResolvedValueOnce(null);
+    const result = await updateUserPassword('u1', 'old', 'new');
+    expect(result.success).toBe(false);
+    expect(result.error).toMatch(/non trouvé/);
+  });
+
+  it('returns error when current password is incorrect', async () => {
+    mockFindUnique.mockResolvedValueOnce({ id: 'u1', password: 'hashed_old' });
+    mockCompareFn.mockResolvedValueOnce(false as never);
+    const result = await updateUserPassword('u1', 'wrong', 'new');
+    expect(result.success).toBe(false);
+    expect(result.error).toMatch(/incorrect/);
+    expect(mockUpdate).not.toHaveBeenCalled();
+  });
+
+  it('hashes new password and updates on success', async () => {
+    mockFindUnique.mockResolvedValueOnce({ id: 'u1', password: 'hashed_old' });
+    mockCompareFn.mockResolvedValueOnce(true as never);
+    mockUpdate.mockResolvedValueOnce({});
+    const result = await updateUserPassword('u1', 'old', 'newpass');
+    expect(mockHashFn).toHaveBeenCalledWith('newpass', 12);
+    expect(mockUpdate).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { password: 'hashed_password' } })
+    );
+    expect(result.success).toBe(true);
+  });
+});
+
+// ── updateUserProfile ─────────────────────────────────────────────────────
+
+describe('updateUserProfile', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns error when email is taken by another user', async () => {
+    mockFindFirst.mockResolvedValueOnce({ id: 'other', email: 'taken@ex.com' });
+    const result = await updateUserProfile('u1', { email: 'taken@ex.com' });
+    expect(result.success).toBe(false);
+    expect(result.error).toMatch(/déjà utilisé/);
+    expect(mockUpdate).not.toHaveBeenCalled();
+  });
+
+  it('updates name and email on success', async () => {
+    mockFindFirst.mockResolvedValueOnce(null); // email not taken
+    mockUpdate.mockResolvedValueOnce({ id: 'u1', email: 'new@ex.com', name: 'New Name' });
+    const result = await updateUserProfile('u1', { name: 'New Name', email: 'new@ex.com' });
+    expect(result.success).toBe(true);
+    expect(result.user).toEqual({ id: 'u1', email: 'new@ex.com', name: 'New Name' });
+  });
+
+  it('skips email uniqueness check when no email provided', async () => {
+    mockUpdate.mockResolvedValueOnce({ id: 'u1', email: 'old@ex.com', name: 'Updated' });
+    const result = await updateUserProfile('u1', { name: 'Updated' });
+    expect(mockFindFirst).not.toHaveBeenCalled();
+    expect(result.success).toBe(true);
+  });
+
+  it('passes correct query to check email uniqueness (excludes self)', async () => {
+    mockFindFirst.mockResolvedValueOnce(null);
+    mockUpdate.mockResolvedValueOnce({ id: 'u1', email: 'new@ex.com', name: null });
+    await updateUserProfile('u1', { email: 'new@ex.com' });
+    expect(mockFindFirst).toHaveBeenCalledWith(
+      expect.objectContaining({ where: expect.objectContaining({ NOT: { id: 'u1' } }) })
+    );
+  });
+});
diff --git a/src/services/__tests__/okrs.test.ts b/src/services/__tests__/okrs.test.ts
new file mode 100644
index 0000000..dc3db33
--- /dev/null
+++ b/src/services/__tests__/okrs.test.ts
@@ -0,0 +1,333 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { createOKR, updateKeyResult, updateOKR, calculateOKRProgress } from '@/services/okrs';
+
+vi.mock('@/services/database', () => {
+  const mockTx = {
+    oKR: {
+      create: vi.fn(),
+      update: vi.fn(),
+      findUnique: vi.fn(),
+    },
+    keyResult: {
+      create: vi.fn(),
+      update: vi.fn(),
+      deleteMany: vi.fn(),
+    },
+  };
+
+  return {
+    prisma: {
+      oKR: {
+        findUnique: vi.fn(),
+        update: vi.fn(),
+      },
+      keyResult: {
+        findUnique: vi.fn(),
+        update: vi.fn(),
+      },
+      $transaction: vi.fn().mockImplementation(async (fn: (tx: typeof mockTx) => unknown) => {
+        if (typeof fn === 'function') return fn(mockTx);
+        return Promise.all(fn as Promise<unknown>[]);
+      }),
+      _mockTx: mockTx,
+    },
+  };
+});
+
+const { prisma } = await import('@/services/database');
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const mockTx = (prisma as any)._mockTx;
+
+// ── calculateOKRProgress ──────────────────────────────────────────────────
+
+describe('calculateOKRProgress', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns 0 when OKR not found', async () => {
+    vi.mocked(prisma.oKR.findUnique).mockResolvedValueOnce(null);
+    const result = await calculateOKRProgress('okr-1');
+    expect(result).toBe(0);
+  });
+
+  it('returns 0 for OKR with empty key results', async () => {
+    vi.mocked(prisma.oKR.findUnique).mockResolvedValueOnce({ id: 'okr-1', keyResults: [] } as never);
+    const result = await calculateOKRProgress('okr-1');
+    expect(result).toBe(0);
+  });
+
+  it('calculates average progress across key results', async () => {
+    vi.mocked(prisma.oKR.findUnique).mockResolvedValueOnce({
+      id: 'okr-1',
+      keyResults: [
+        { currentValue: 50, targetValue: 100 }, // 50%
+        { currentValue: 100, targetValue: 100 }, // 100%
+      ],
+    } as never);
+    const result = await calculateOKRProgress('okr-1');
+    expect(result).toBe(75);
+  });
+
+  it('caps individual KR progress at 100%', async () => {
+    vi.mocked(prisma.oKR.findUnique).mockResolvedValueOnce({
+      id: 'okr-1',
+      keyResults: [
+        { currentValue: 200, targetValue: 100 }, // over 100% → capped at 100
+        { currentValue: 0, targetValue: 100 }, // 0%
+      ],
+    } as never);
+    const result = await calculateOKRProgress('okr-1');
+    expect(result).toBe(50); // (100 + 0) / 2
+  });
+
+  it('returns 0 when targetValue is 0 (avoids division by zero)', async () => {
+    vi.mocked(prisma.oKR.findUnique).mockResolvedValueOnce({
+      id: 'okr-1',
+      keyResults: [{ currentValue: 50, targetValue: 0 }],
+    } as never);
+    const result = await calculateOKRProgress('okr-1');
+    expect(result).toBe(0);
+  });
+});
+
+// ── createOKR ─────────────────────────────────────────────────────────────
+
+describe('createOKR', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('creates OKR with NOT_STARTED status in transaction', async () => {
+    const createdOKR = { id: 'okr-1', teamMemberId: 'tm-1', objective: 'Grow revenue', status: 'NOT_STARTED' };
+    mockTx.oKR.create.mockResolvedValueOnce(createdOKR);
+    mockTx.keyResult.create.mockResolvedValue({ id: 'kr-1' });
+
+    const result = await createOKR(
+      'tm-1',
+      'Grow revenue',
+      null,
+      'Q1-2026',
+      new Date(),
+      new Date(),
+      [{ title: 'KR1', targetValue: 100, unit: '%', order: 0 }]
+    );
+
+    expect(vi.mocked(prisma.$transaction)).toHaveBeenCalledTimes(1);
+    expect(mockTx.oKR.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        data: expect.objectContaining({ status: 'NOT_STARTED', teamMemberId: 'tm-1' }),
+      })
+    );
+    expect(result).toMatchObject({ id: 'okr-1' });
+  });
+
+  it('creates all key results with NOT_STARTED status', async () => {
+    const createdOKR = { id: 'okr-1' };
+    mockTx.oKR.create.mockResolvedValueOnce(createdOKR);
+    mockTx.keyResult.create.mockResolvedValue({ id: 'kr-1', status: 'NOT_STARTED' });
+
+    const keyResults = [
+      { title: 'KR1', targetValue: 100, unit: '%', order: 0 },
+      { title: 'KR2', targetValue: 50, unit: 'units', order: 1 },
+    ];
+    await createOKR('tm-1', 'Obj', null, 'Q1', new Date(), new Date(), keyResults);
+
+    expect(mockTx.keyResult.create).toHaveBeenCalledTimes(2);
+    expect(mockTx.keyResult.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ status: 'NOT_STARTED', currentValue: 0 }) })
+    );
+  });
+
+  it('uses index as order when order is not provided', async () => {
+    mockTx.oKR.create.mockResolvedValueOnce({ id: 'okr-1' });
+    mockTx.keyResult.create.mockResolvedValue({ id: 'kr-1' });
+
+    // Pass keyResults with explicit order
+    await createOKR('tm-1', 'Obj', null, 'Q1', new Date(), new Date(), [
+      { title: 'KR1', targetValue: 100, unit: '%', order: 5 },
+    ]);
+
+    expect(mockTx.keyResult.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ order: 5 }) })
+    );
+  });
+
+  it('defaults unit to % when unit is empty string', async () => {
+    mockTx.oKR.create.mockResolvedValueOnce({ id: 'okr-1' });
+    mockTx.keyResult.create.mockResolvedValue({ id: 'kr-1' });
+
+    await createOKR('tm-1', 'Obj', null, 'Q1', new Date(), new Date(), [
+      { title: 'KR1', targetValue: 100, unit: '', order: 0 },
+    ]);
+
+    expect(mockTx.keyResult.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ unit: '%' }) })
+    );
+  });
+});
+
+// ── updateKeyResult ───────────────────────────────────────────────────────
+
+describe('updateKeyResult', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  function makeKR(currentValue: number, targetValue: number, okrStatus = 'NOT_STARTED') {
+    return {
+      id: 'kr-1',
+      targetValue,
+      notes: null,
+      status: 'NOT_STARTED',
+      okr: { id: 'okr-1', status: okrStatus, keyResults: [{ currentValue, targetValue }] },
+    };
+  }
+
+  it('throws when key result not found', async () => {
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(null);
+    await expect(updateKeyResult('kr-1', 50, null)).rejects.toThrow('Key Result not found');
+  });
+
+  it('sets status to NOT_STARTED when progress is 0', async () => {
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(makeKR(0, 100) as never);
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(makeKR(0, 100) as never);
+    await updateKeyResult('kr-1', 0, null);
+    expect(vi.mocked(prisma.keyResult.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ status: 'NOT_STARTED' }) })
+    );
+  });
+
+  it('sets status to AT_RISK when progress is below 50%', async () => {
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(makeKR(0, 100) as never);
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(makeKR(30, 100) as never);
+    await updateKeyResult('kr-1', 30, null);
+    expect(vi.mocked(prisma.keyResult.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ status: 'AT_RISK' }) })
+    );
+  });
+
+  it('sets status to IN_PROGRESS when progress is 50% or more (but less than 100%)', async () => {
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(makeKR(0, 100) as never);
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(makeKR(70, 100) as never);
+    await updateKeyResult('kr-1', 70, null);
+    expect(vi.mocked(prisma.keyResult.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ status: 'IN_PROGRESS' }) })
+    );
+  });
+
+  it('sets status to COMPLETED when progress reaches 100%', async () => {
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(makeKR(0, 100) as never);
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(makeKR(100, 100) as never);
+    await updateKeyResult('kr-1', 100, null);
+    expect(vi.mocked(prisma.keyResult.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ status: 'COMPLETED' }) })
+    );
+  });
+
+  it('updates OKR status to IN_PROGRESS when progress > 0', async () => {
+    const kr = makeKR(0, 100, 'NOT_STARTED');
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(kr as never);
+    // update returns KR with okr having keyResults at 50%
+    const updatedKr = {
+      ...kr,
+      okr: { id: 'okr-1', status: 'NOT_STARTED', keyResults: [{ currentValue: 50, targetValue: 100 }] },
+    };
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(updatedKr as never);
+
+    await updateKeyResult('kr-1', 50, null);
+
+    expect(vi.mocked(prisma.oKR.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { status: 'IN_PROGRESS' } })
+    );
+  });
+
+  it('updates OKR status to COMPLETED when all KRs are 100%', async () => {
+    const kr = makeKR(0, 100, 'IN_PROGRESS');
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(kr as never);
+    const updatedKr = {
+      ...kr,
+      okr: { id: 'okr-1', status: 'IN_PROGRESS', keyResults: [{ currentValue: 100, targetValue: 100 }] },
+    };
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(updatedKr as never);
+
+    await updateKeyResult('kr-1', 100, null);
+
+    expect(vi.mocked(prisma.oKR.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { status: 'COMPLETED' } })
+    );
+  });
+
+  it('does not update OKR status if it has not changed', async () => {
+    const kr = makeKR(0, 100, 'IN_PROGRESS');
+    vi.mocked(prisma.keyResult.findUnique).mockResolvedValueOnce(kr as never);
+    const updatedKr = {
+      ...kr,
+      okr: { id: 'okr-1', status: 'IN_PROGRESS', keyResults: [{ currentValue: 60, targetValue: 100 }] },
+    };
+    vi.mocked(prisma.keyResult.update).mockResolvedValueOnce(updatedKr as never);
+
+    await updateKeyResult('kr-1', 60, null);
+
+    expect(vi.mocked(prisma.oKR.update)).not.toHaveBeenCalled();
+  });
+});
+
+// ── updateOKR ─────────────────────────────────────────────────────────────
+
+describe('updateOKR', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('updates OKR fields in transaction', async () => {
+    mockTx.oKR.update.mockResolvedValueOnce({});
+    mockTx.oKR.findUnique.mockResolvedValueOnce({ id: 'okr-1', status: 'IN_PROGRESS', keyResults: [] });
+
+    await updateOKR('okr-1', { objective: 'New objective', status: 'IN_PROGRESS' });
+
+    expect(mockTx.oKR.update).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: { id: 'okr-1' },
+        data: expect.objectContaining({ objective: 'New objective', status: 'IN_PROGRESS' }),
+      })
+    );
+  });
+
+  it('deletes key results when delete list provided', async () => {
+    mockTx.oKR.update.mockResolvedValueOnce({});
+    mockTx.keyResult.deleteMany.mockResolvedValueOnce({ count: 1 });
+    mockTx.oKR.findUnique.mockResolvedValueOnce({ id: 'okr-1', status: 'NOT_STARTED', keyResults: [] });
+
+    await updateOKR('okr-1', {}, { delete: ['kr-1', 'kr-2'] });
+
+    expect(mockTx.keyResult.deleteMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { id: { in: ['kr-1', 'kr-2'] }, okrId: 'okr-1' } })
+    );
+  });
+
+  it('creates new key results when create list provided', async () => {
+    mockTx.oKR.update.mockResolvedValueOnce({});
+    mockTx.keyResult.create.mockResolvedValue({ id: 'kr-new' });
+    mockTx.oKR.findUnique.mockResolvedValueOnce({ id: 'okr-1', status: 'NOT_STARTED', keyResults: [] });
+
+    await updateOKR('okr-1', {}, {
+      create: [{ title: 'New KR', targetValue: 100, unit: '%', order: 0 }],
+    });
+
+    expect(mockTx.keyResult.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ title: 'New KR', currentValue: 0, status: 'NOT_STARTED' }) })
+    );
+  });
+
+  it('throws when OKR not found after update', async () => {
+    mockTx.oKR.update.mockResolvedValueOnce({});
+    mockTx.oKR.findUnique.mockResolvedValueOnce(null);
+
+    await expect(updateOKR('okr-1', {})).rejects.toThrow('OKR not found after update');
+  });
+
+  it('includes progress in returned OKR', async () => {
+    mockTx.oKR.update.mockResolvedValueOnce({});
+    mockTx.oKR.findUnique.mockResolvedValueOnce({
+      id: 'okr-1',
+      status: 'IN_PROGRESS',
+      keyResults: [{ currentValue: 50, targetValue: 100 }],
+    });
+
+    const result = await updateOKR('okr-1', {});
+    expect(result).toMatchObject({ id: 'okr-1', progress: 50 });
+  });
+});
diff --git a/src/services/__tests__/session-permissions.test.ts b/src/services/__tests__/session-permissions.test.ts
new file mode 100644
index 0000000..4e8f80a
--- /dev/null
+++ b/src/services/__tests__/session-permissions.test.ts
@@ -0,0 +1,156 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import {
+  createSessionPermissionChecks,
+  withAdminFallback,
+  canDeleteByOwner,
+} from '@/services/session-permissions';
+
+vi.mock('@/services/teams', () => ({
+  isAdminOfUser: vi.fn(),
+}));
+
+const { isAdminOfUser } = await import('@/services/teams');
+const mockIsAdminOfUser = vi.mocked(isAdminOfUser);
+
+// Factory for mock Prisma model delegate
+function makeModel(countResult: number, ownerId: string | null = 'owner-1') {
+  return {
+    count: vi.fn().mockResolvedValue(countResult),
+    findUnique: vi.fn().mockResolvedValue(ownerId ? { userId: ownerId } : null),
+  };
+}
+
+describe('createSessionPermissionChecks', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockIsAdminOfUser.mockResolvedValue(false);
+  });
+
+  describe('canAccess', () => {
+    it('returns true when user has direct access (count > 0)', async () => {
+      const { canAccess } = createSessionPermissionChecks(makeModel(1));
+      expect(await canAccess('session-1', 'user-1')).toBe(true);
+    });
+
+    it('returns true when no direct access but user is team admin', async () => {
+      mockIsAdminOfUser.mockResolvedValue(true);
+      const { canAccess } = createSessionPermissionChecks(makeModel(0, 'owner-1'));
+      expect(await canAccess('session-1', 'admin-1')).toBe(true);
+    });
+
+    it('returns false when no direct access and not admin', async () => {
+      const { canAccess } = createSessionPermissionChecks(makeModel(0, 'owner-1'));
+      expect(await canAccess('session-1', 'stranger')).toBe(false);
+    });
+
+    it('returns false when no direct access and session owner not found', async () => {
+      const { canAccess } = createSessionPermissionChecks(makeModel(0, null));
+      expect(await canAccess('session-1', 'anyone')).toBe(false);
+    });
+  });
+
+  describe('canEdit', () => {
+    it('returns true when user is owner or editor (count > 0)', async () => {
+      const { canEdit } = createSessionPermissionChecks(makeModel(1));
+      expect(await canEdit('session-1', 'editor-1')).toBe(true);
+    });
+
+    it('returns false for viewer (count = 0) when not admin', async () => {
+      const { canEdit } = createSessionPermissionChecks(makeModel(0, 'owner-1'));
+      expect(await canEdit('session-1', 'viewer-1')).toBe(false);
+    });
+
+    it('returns true for viewer when user is team admin', async () => {
+      mockIsAdminOfUser.mockResolvedValue(true);
+      const { canEdit } = createSessionPermissionChecks(makeModel(0, 'owner-1'));
+      expect(await canEdit('session-1', 'admin-1')).toBe(true);
+    });
+  });
+
+  describe('canDelete', () => {
+    it('returns true for session owner', async () => {
+      const { canDelete } = createSessionPermissionChecks(makeModel(1, 'owner-1'));
+      expect(await canDelete('session-1', 'owner-1')).toBe(true);
+    });
+
+    it('returns false for non-owner even with EDITOR role', async () => {
+      const { canDelete } = createSessionPermissionChecks(makeModel(1, 'owner-1'));
+      expect(await canDelete('session-1', 'editor-1')).toBe(false);
+    });
+
+    it('returns true when user is team admin of the owner', async () => {
+      mockIsAdminOfUser.mockResolvedValue(true);
+      const { canDelete } = createSessionPermissionChecks(makeModel(0, 'owner-1'));
+      expect(await canDelete('session-1', 'admin-1')).toBe(true);
+    });
+
+    it('returns false when session not found', async () => {
+      const { canDelete } = createSessionPermissionChecks(makeModel(0, null));
+      expect(await canDelete('session-1', 'anyone')).toBe(false);
+    });
+  });
+});
+
+describe('withAdminFallback', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockIsAdminOfUser.mockResolvedValue(false);
+  });
+
+  it('returns true immediately when hasDirectAccess is true (no admin check)', async () => {
+    const getOwnerId = vi.fn();
+    const result = await withAdminFallback(true, getOwnerId, 'session-1', 'user-1');
+    expect(result).toBe(true);
+    expect(getOwnerId).not.toHaveBeenCalled();
+    expect(mockIsAdminOfUser).not.toHaveBeenCalled();
+  });
+
+  it('falls back to admin check when no direct access', async () => {
+    mockIsAdminOfUser.mockResolvedValue(true);
+    const getOwnerId = vi.fn().mockResolvedValue('owner-1');
+    const result = await withAdminFallback(false, getOwnerId, 'session-1', 'admin-1');
+    expect(result).toBe(true);
+    expect(mockIsAdminOfUser).toHaveBeenCalledWith('owner-1', 'admin-1');
+  });
+
+  it('returns false when no direct access and not admin', async () => {
+    const getOwnerId = vi.fn().mockResolvedValue('owner-1');
+    const result = await withAdminFallback(false, getOwnerId, 'session-1', 'stranger');
+    expect(result).toBe(false);
+  });
+
+  it('returns false when owner not found', async () => {
+    const getOwnerId = vi.fn().mockResolvedValue(null);
+    const result = await withAdminFallback(false, getOwnerId, 'session-1', 'anyone');
+    expect(result).toBe(false);
+    expect(mockIsAdminOfUser).not.toHaveBeenCalled();
+  });
+});
+
+describe('canDeleteByOwner', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockIsAdminOfUser.mockResolvedValue(false);
+  });
+
+  it('returns true when userId matches ownerId', async () => {
+    const getOwnerId = vi.fn().mockResolvedValue('user-1');
+    expect(await canDeleteByOwner(getOwnerId, 'session-1', 'user-1')).toBe(true);
+  });
+
+  it('returns false when userId does not match and not admin', async () => {
+    const getOwnerId = vi.fn().mockResolvedValue('owner-1');
+    expect(await canDeleteByOwner(getOwnerId, 'session-1', 'other')).toBe(false);
+  });
+
+  it('returns true when user is admin of owner', async () => {
+    mockIsAdminOfUser.mockResolvedValue(true);
+    const getOwnerId = vi.fn().mockResolvedValue('owner-1');
+    expect(await canDeleteByOwner(getOwnerId, 'session-1', 'admin-1')).toBe(true);
+  });
+
+  it('returns false when session not found (ownerId is null)', async () => {
+    const getOwnerId = vi.fn().mockResolvedValue(null);
+    expect(await canDeleteByOwner(getOwnerId, 'session-1', 'anyone')).toBe(false);
+  });
+});
diff --git a/src/services/__tests__/session-queries.test.ts b/src/services/__tests__/session-queries.test.ts
new file mode 100644
index 0000000..410f843
--- /dev/null
+++ b/src/services/__tests__/session-queries.test.ts
@@ -0,0 +1,248 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import {
+  mergeSessionsByUserId,
+  fetchTeamCollaboratorSessions,
+  getSessionByIdGeneric,
+} from '@/services/session-queries';
+
+vi.mock('@/services/teams', () => ({
+  isAdminOfUser: vi.fn().mockResolvedValue(false),
+  getTeamMemberIdsForAdminTeams: vi.fn().mockResolvedValue([]),
+}));
+
+const { isAdminOfUser } = await import('@/services/teams');
+const mockIsAdminOfUser = vi.mocked(isAdminOfUser);
+
+// ── Shared test data ───────────────────────────────────────────────────────
+
+const USER_ID = 'user-1';
+
+function makeSession(overrides: Partial<{
+  id: string; updatedAt: Date; userId: string;
+  shares: Array<{ userId: string; role?: string }>;
+}> = {}) {
+  return {
+    id: 's1',
+    updatedAt: new Date('2024-06-01'),
+    userId: USER_ID,
+    user: { id: USER_ID, name: 'Alice', email: 'alice@example.com' },
+    shares: [],
+    ...overrides,
+  };
+}
+
+// ── mergeSessionsByUserId ──────────────────────────────────────────────────
+
+describe('mergeSessionsByUserId', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('marks owned sessions with isOwner=true and role=OWNER', async () => {
+    const s = makeSession();
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([s]),
+      vi.fn().mockResolvedValue([]),
+      USER_ID
+    );
+    expect(result).toHaveLength(1);
+    expect(result[0]).toMatchObject({ id: 's1', isOwner: true, role: 'OWNER' });
+  });
+
+  it('marks shared sessions with isOwner=false and role from share', async () => {
+    const s = makeSession({ id: 's2', userId: 'other' });
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([]),
+      vi.fn().mockResolvedValue([{ session: s, role: 'VIEWER', createdAt: new Date() }]),
+      USER_ID
+    );
+    expect(result[0]).toMatchObject({ id: 's2', isOwner: false, role: 'VIEWER' });
+  });
+
+  it('sorts merged list by updatedAt descending', async () => {
+    const older = makeSession({ id: 's1', updatedAt: new Date('2024-01-01') });
+    const newer = makeSession({ id: 's2', updatedAt: new Date('2024-06-01') });
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([older, newer]),
+      vi.fn().mockResolvedValue([]),
+      USER_ID
+    );
+    expect(result[0].id).toBe('s2');
+    expect(result[1].id).toBe('s1');
+  });
+
+  it('merges owned and shared sessions together', async () => {
+    const owned = makeSession({ id: 'own' });
+    const shared = makeSession({ id: 'shared', userId: 'other', updatedAt: new Date('2020-01-01') });
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([owned]),
+      vi.fn().mockResolvedValue([{ session: shared, role: 'EDITOR', createdAt: new Date() }]),
+      USER_ID
+    );
+    expect(result).toHaveLength(2);
+    expect(result.map((s) => s.id)).toContain('own');
+    expect(result.map((s) => s.id)).toContain('shared');
+  });
+
+  it('returns empty array when no sessions', async () => {
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([]),
+      vi.fn().mockResolvedValue([]),
+      USER_ID
+    );
+    expect(result).toHaveLength(0);
+  });
+
+  it('applies resolveParticipant callback to each session', async () => {
+    const s = makeSession();
+    const resolveParticipant = vi.fn().mockResolvedValue({ extra: 'data' });
+    const result = await mergeSessionsByUserId(
+      vi.fn().mockResolvedValue([s]),
+      vi.fn().mockResolvedValue([]),
+      USER_ID,
+      resolveParticipant
+    );
+    expect(resolveParticipant).toHaveBeenCalledWith(expect.objectContaining({ id: 's1' }));
+    expect((result[0] as typeof result[0] & { extra: string }).extra).toBe('data');
+  });
+});
+
+// ── fetchTeamCollaboratorSessions ──────────────────────────────────────────
+
+describe('fetchTeamCollaboratorSessions', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns empty array when team has no members', async () => {
+    const result = await fetchTeamCollaboratorSessions(
+      vi.fn(),
+      vi.fn().mockResolvedValue([]),
+      USER_ID
+    );
+    expect(result).toHaveLength(0);
+  });
+
+  it('marks sessions with isTeamCollab=true, canEdit=true, role=VIEWER', async () => {
+    const s = makeSession({ id: 'team-s', userId: 'member-1' });
+    const result = await fetchTeamCollaboratorSessions(
+      vi.fn().mockResolvedValue([s]),
+      vi.fn().mockResolvedValue(['member-1']),
+      USER_ID
+    );
+    expect(result[0]).toMatchObject({ id: 'team-s', isOwner: false, role: 'VIEWER', isTeamCollab: true, canEdit: true });
+  });
+
+  it('calls fetchTeamSessions with team member ids', async () => {
+    const fetchTeamSessions = vi.fn().mockResolvedValue([]);
+    await fetchTeamCollaboratorSessions(
+      fetchTeamSessions,
+      vi.fn().mockResolvedValue(['m1', 'm2']),
+      USER_ID
+    );
+    expect(fetchTeamSessions).toHaveBeenCalledWith(['m1', 'm2'], USER_ID);
+  });
+
+  it('applies resolveParticipant callback', async () => {
+    const s = makeSession({ id: 't-s', userId: 'member-1' });
+    const resolveParticipant = vi.fn().mockResolvedValue({ resolved: true });
+    const result = await fetchTeamCollaboratorSessions(
+      vi.fn().mockResolvedValue([s]),
+      vi.fn().mockResolvedValue(['member-1']),
+      USER_ID,
+      resolveParticipant
+    );
+    expect(resolveParticipant).toHaveBeenCalled();
+    expect((result[0] as typeof result[0] & { resolved: boolean }).resolved).toBe(true);
+  });
+});
+
+// ── getSessionByIdGeneric ──────────────────────────────────────────────────
+
+describe('getSessionByIdGeneric', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockIsAdminOfUser.mockResolvedValue(false);
+  });
+
+  it('returns session with isOwner=true when user is owner', async () => {
+    const s = makeSession({ userId: USER_ID, shares: [] });
+    const result = await getSessionByIdGeneric(
+      's1', USER_ID,
+      vi.fn().mockResolvedValue(s),
+      vi.fn()
+    );
+    expect(result).toMatchObject({ isOwner: true, role: 'OWNER', canEdit: true });
+  });
+
+  it('returns session with EDITOR role and canEdit=true for editor share', async () => {
+    const s = makeSession({ userId: 'owner-1', shares: [{ userId: USER_ID, role: 'EDITOR' }] });
+    const result = await getSessionByIdGeneric(
+      's1', USER_ID,
+      vi.fn().mockResolvedValue(s),
+      vi.fn()
+    );
+    expect(result).toMatchObject({ isOwner: false, role: 'EDITOR', canEdit: true });
+  });
+
+  it('returns session with VIEWER role and canEdit=false for viewer share', async () => {
+    const s = makeSession({ userId: 'owner-1', shares: [{ userId: USER_ID, role: 'VIEWER' }] });
+    const result = await getSessionByIdGeneric(
+      's1', USER_ID,
+      vi.fn().mockResolvedValue(s),
+      vi.fn()
+    );
+    expect(result).toMatchObject({ isOwner: false, role: 'VIEWER', canEdit: false });
+  });
+
+  it('returns null when session not found anywhere', async () => {
+    const result = await getSessionByIdGeneric(
+      'missing', USER_ID,
+      vi.fn().mockResolvedValue(null),
+      vi.fn().mockResolvedValue(null)
+    );
+    expect(result).toBeNull();
+  });
+
+  it('falls back to admin check when no direct access', async () => {
+    mockIsAdminOfUser.mockResolvedValue(true);
+    const s = makeSession({ userId: 'owner-1', shares: [] });
+    const result = await getSessionByIdGeneric(
+      's1', 'admin-1',
+      vi.fn().mockResolvedValue(null), // no direct access
+      vi.fn().mockResolvedValue(s)     // but found by id
+    );
+    expect(result).not.toBeNull();
+    expect(mockIsAdminOfUser).toHaveBeenCalledWith('owner-1', 'admin-1');
+  });
+
+  it('returns null when no direct access and not admin', async () => {
+    const s = makeSession({ userId: 'owner-1', shares: [] });
+    const result = await getSessionByIdGeneric(
+      's1', 'stranger',
+      vi.fn().mockResolvedValue(null),
+      vi.fn().mockResolvedValue(s)
+    );
+    expect(result).toBeNull();
+  });
+
+  it('grants canEdit=true to team admin viewing member session', async () => {
+    mockIsAdminOfUser.mockResolvedValue(true);
+    const s = makeSession({ userId: 'owner-1', shares: [] });
+    const result = await getSessionByIdGeneric(
+      's1', 'admin-1',
+      vi.fn().mockResolvedValue(null),
+      vi.fn().mockResolvedValue(s)
+    );
+    expect(result?.canEdit).toBe(true);
+  });
+
+  it('applies resolveParticipant callback when provided', async () => {
+    const s = makeSession({ userId: USER_ID, shares: [] });
+    const resolveParticipant = vi.fn().mockResolvedValue({ participantName: 'Bob' });
+    const result = await getSessionByIdGeneric(
+      's1', USER_ID,
+      vi.fn().mockResolvedValue(s),
+      vi.fn(),
+      resolveParticipant
+    );
+    expect(resolveParticipant).toHaveBeenCalledWith(expect.objectContaining({ id: 's1' }));
+    expect((result as typeof result & { participantName: string })?.participantName).toBe('Bob');
+  });
+});
diff --git a/src/services/__tests__/session-share-events.test.ts b/src/services/__tests__/session-share-events.test.ts
new file mode 100644
index 0000000..89f4aaf
--- /dev/null
+++ b/src/services/__tests__/session-share-events.test.ts
@@ -0,0 +1,218 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { createShareAndEventHandlers } from '@/services/session-share-events';
+
+vi.mock('@/services/database', () => ({
+  prisma: {
+    user: {
+      findUnique: vi.fn(),
+    },
+  },
+}));
+
+const { prisma } = await import('@/services/database');
+const mockFindUnique = vi.mocked(prisma.user.findUnique);
+
+// ── Mock delegate factories ────────────────────────────────────────────────
+
+const OWNER_ID = 'owner-1';
+const SESSION_ID = 'session-1';
+
+function makeSessionModel(session: object | null = { id: SESSION_ID, userId: OWNER_ID }) {
+  return { findFirst: vi.fn().mockResolvedValue(session) };
+}
+
+function makeShareModel() {
+  return {
+    upsert: vi.fn().mockResolvedValue({ id: 'share-1', userId: 'target-1', role: 'EDITOR' }),
+    deleteMany: vi.fn().mockResolvedValue({ count: 1 }),
+    findMany: vi.fn().mockResolvedValue([]),
+  };
+}
+
+function makeEventModel(eventResult = { id: 'e1', sessionId: SESSION_ID, userId: OWNER_ID, type: 'UPDATE', payload: '{}', createdAt: new Date() }) {
+  return {
+    create: vi.fn().mockResolvedValue(eventResult),
+    findMany: vi.fn().mockResolvedValue([]),
+    findFirst: vi.fn().mockResolvedValue(null),
+    deleteMany: vi.fn().mockResolvedValue({ count: 0 }),
+  };
+}
+
+const canAccess = vi.fn().mockResolvedValue(true);
+
+// ── share ──────────────────────────────────────────────────────────────────
+
+describe('share', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('shares session with target user', async () => {
+    const targetUser = { id: 'target-1', email: 'bob@example.com', name: 'Bob' };
+    mockFindUnique.mockResolvedValue(targetUser);
+    const shareModel = makeShareModel();
+    const { share } = createShareAndEventHandlers(makeSessionModel(), shareModel, makeEventModel(), canAccess);
+
+    await share(SESSION_ID, OWNER_ID, 'bob@example.com', 'EDITOR');
+
+    expect(shareModel.upsert).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: { sessionId_userId: { sessionId: SESSION_ID, userId: 'target-1' } },
+        create: expect.objectContaining({ sessionId: SESSION_ID, userId: 'target-1', role: 'EDITOR' }),
+      })
+    );
+  });
+
+  it('throws when target user is not found', async () => {
+    mockFindUnique.mockResolvedValue(null);
+    const { share } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), makeEventModel(), canAccess);
+    await expect(share(SESSION_ID, OWNER_ID, 'ghost@example.com')).rejects.toThrow('User not found');
+  });
+
+  it('throws when trying to share with yourself', async () => {
+    mockFindUnique.mockResolvedValue({ id: OWNER_ID, email: 'owner@example.com', name: 'Owner' });
+    const { share } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), makeEventModel(), canAccess);
+    await expect(share(SESSION_ID, OWNER_ID, 'owner@example.com')).rejects.toThrow('Cannot share session with yourself');
+  });
+
+  it('throws when session not owned by caller', async () => {
+    mockFindUnique.mockResolvedValue({ id: 'target-1', email: 'bob@example.com', name: 'Bob' });
+    const sessionModel = makeSessionModel(null); // findFirst returns null → not owned
+    const { share } = createShareAndEventHandlers(sessionModel, makeShareModel(), makeEventModel(), canAccess);
+    await expect(share(SESSION_ID, 'not-owner', 'bob@example.com')).rejects.toThrow('Session not found or not owned');
+  });
+
+  it('defaults role to EDITOR', async () => {
+    const targetUser = { id: 'target-1', email: 'bob@example.com', name: 'Bob' };
+    mockFindUnique.mockResolvedValue(targetUser);
+    const shareModel = makeShareModel();
+    const { share } = createShareAndEventHandlers(makeSessionModel(), shareModel, makeEventModel(), canAccess);
+
+    await share(SESSION_ID, OWNER_ID, 'bob@example.com');
+
+    expect(shareModel.upsert).toHaveBeenCalledWith(
+      expect.objectContaining({ create: expect.objectContaining({ role: 'EDITOR' }) })
+    );
+  });
+});
+
+// ── removeShare ────────────────────────────────────────────────────────────
+
+describe('removeShare', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('removes share when caller is owner', async () => {
+    const shareModel = makeShareModel();
+    const { removeShare } = createShareAndEventHandlers(makeSessionModel(), shareModel, makeEventModel(), canAccess);
+
+    await removeShare(SESSION_ID, OWNER_ID, 'target-1');
+
+    expect(shareModel.deleteMany).toHaveBeenCalledWith({ where: { sessionId: SESSION_ID, userId: 'target-1' } });
+  });
+
+  it('throws when session not owned by caller', async () => {
+    const { removeShare } = createShareAndEventHandlers(makeSessionModel(null), makeShareModel(), makeEventModel(), canAccess);
+    await expect(removeShare(SESSION_ID, 'not-owner', 'target-1')).rejects.toThrow('Session not found or not owned');
+  });
+});
+
+// ── createEvent ────────────────────────────────────────────────────────────
+
+describe('createEvent', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('creates event with correct data', async () => {
+    const eventModel = makeEventModel();
+    const { createEvent } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    await createEvent(SESSION_ID, OWNER_ID, 'UPDATE' as never, { key: 'value' });
+
+    expect(eventModel.create).toHaveBeenCalledWith({
+      data: {
+        sessionId: SESSION_ID,
+        userId: OWNER_ID,
+        type: 'UPDATE',
+        payload: JSON.stringify({ key: 'value' }),
+      },
+    });
+  });
+
+  it('triggers fire-and-forget cleanup after event creation', async () => {
+    const eventModel = makeEventModel();
+    const { createEvent } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    await createEvent(SESSION_ID, OWNER_ID, 'UPDATE' as never, {});
+
+    // deleteMany is called as fire-and-forget (not awaited, but should be invoked)
+    await vi.waitFor(() => expect(eventModel.deleteMany).toHaveBeenCalledTimes(1));
+    expect(eventModel.deleteMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { createdAt: expect.objectContaining({ lt: expect.any(Date) }) } })
+    );
+  });
+
+  it('does not throw when cleanup fails', async () => {
+    const eventModel = makeEventModel();
+    eventModel.deleteMany.mockRejectedValue(new Error('DB error'));
+    const { createEvent } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    await expect(createEvent(SESSION_ID, OWNER_ID, 'UPDATE' as never, {})).resolves.not.toThrow();
+  });
+
+  it('returns the created event', async () => {
+    const created = { id: 'e42', sessionId: SESSION_ID, userId: OWNER_ID, type: 'UPDATE', payload: '{}', createdAt: new Date() };
+    const eventModel = makeEventModel(created);
+    const { createEvent } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    const result = await createEvent(SESSION_ID, OWNER_ID, 'UPDATE' as never, {});
+    expect(result.id).toBe('e42');
+  });
+});
+
+// ── getEvents ──────────────────────────────────────────────────────────────
+
+describe('getEvents', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('fetches all events for a session without since filter', async () => {
+    const eventModel = makeEventModel();
+    const { getEvents } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    await getEvents(SESSION_ID);
+
+    expect(eventModel.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { sessionId: SESSION_ID } })
+    );
+  });
+
+  it('filters events by since timestamp when provided', async () => {
+    const since = new Date('2024-01-01');
+    const eventModel = makeEventModel();
+    const { getEvents } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), eventModel, canAccess);
+
+    await getEvents(SESSION_ID, since);
+
+    expect(eventModel.findMany).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { sessionId: SESSION_ID, createdAt: { gt: since } } })
+    );
+  });
+});
+
+// ── getShares ──────────────────────────────────────────────────────────────
+
+describe('getShares', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns shares when user has access', async () => {
+    const shares = [{ id: 'sh-1', user: { id: 'u1', name: 'Bob', email: 'bob@ex.com' } }];
+    const shareModel = makeShareModel();
+    shareModel.findMany.mockResolvedValue(shares);
+    const { getShares } = createShareAndEventHandlers(makeSessionModel(), shareModel, makeEventModel(), canAccess);
+
+    const result = await getShares(SESSION_ID, OWNER_ID);
+    expect(result).toEqual(shares);
+  });
+
+  it('throws Access denied when user has no access', async () => {
+    const noAccess = vi.fn().mockResolvedValue(false);
+    const { getShares } = createShareAndEventHandlers(makeSessionModel(), makeShareModel(), makeEventModel(), noAccess);
+    await expect(getShares(SESSION_ID, 'stranger')).rejects.toThrow('Access denied');
+  });
+});
diff --git a/src/services/__tests__/teams.test.ts b/src/services/__tests__/teams.test.ts
new file mode 100644
index 0000000..946ec6e
--- /dev/null
+++ b/src/services/__tests__/teams.test.ts
@@ -0,0 +1,244 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// Make React cache a transparent pass-through in tests
+vi.mock('react', () => ({
+  cache: (fn: unknown) => fn,
+}));
+
+vi.mock('@/services/database', () => {
+  const mockTx = {
+    team: { create: vi.fn() },
+    teamMember: { create: vi.fn() },
+  };
+  return {
+    prisma: {
+      team: { create: vi.fn(), update: vi.fn() },
+      teamMember: {
+        findUnique: vi.fn(),
+        create: vi.fn(),
+        findMany: vi.fn(),
+      },
+      $transaction: vi.fn().mockImplementation(async (fn: (tx: typeof mockTx) => unknown) => fn(mockTx)),
+      _mockTx: mockTx,
+    },
+  };
+});
+
+import { createTeam, addTeamMember, isAdminOfUser, getTeamMemberIdsForAdminTeams, getUserTeams } from '@/services/teams';
+
+const { prisma } = await import('@/services/database');
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+const mockTx = (prisma as any)._mockTx;
+
+// ── createTeam ────────────────────────────────────────────────────────────
+
+describe('createTeam', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('creates team and adds creator as ADMIN in a transaction', async () => {
+    const team = { id: 'team-1', name: 'Alpha', description: null, createdById: 'user-1' };
+    mockTx.team.create.mockResolvedValueOnce(team);
+    mockTx.teamMember.create.mockResolvedValueOnce({});
+
+    const result = await createTeam('Alpha', null, 'user-1');
+
+    expect(vi.mocked(prisma.$transaction)).toHaveBeenCalledTimes(1);
+    expect(mockTx.team.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { name: 'Alpha', description: null, createdById: 'user-1' } })
+    );
+    expect(mockTx.teamMember.create).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { teamId: 'team-1', userId: 'user-1', role: 'ADMIN' } })
+    );
+    expect(result).toEqual(team);
+  });
+
+  it('returns the created team (not the member)', async () => {
+    const team = { id: 'team-2', name: 'Beta', description: 'desc', createdById: 'user-2' };
+    mockTx.team.create.mockResolvedValueOnce(team);
+    mockTx.teamMember.create.mockResolvedValueOnce({ id: 'member-1' });
+
+    const result = await createTeam('Beta', 'desc', 'user-2');
+    expect(result).toEqual(team);
+  });
+});
+
+// ── addTeamMember ─────────────────────────────────────────────────────────
+
+describe('addTeamMember', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('throws when user is already a member', async () => {
+    vi.mocked(prisma.teamMember.findUnique).mockResolvedValueOnce({
+      teamId: 'team-1', userId: 'user-1', role: 'MEMBER',
+    } as never);
+
+    await expect(addTeamMember('team-1', 'user-1')).rejects.toThrow('déjà membre');
+    expect(vi.mocked(prisma.teamMember.create)).not.toHaveBeenCalled();
+  });
+
+  it('creates member with MEMBER role by default', async () => {
+    vi.mocked(prisma.teamMember.findUnique).mockResolvedValueOnce(null);
+    vi.mocked(prisma.teamMember.create).mockResolvedValueOnce({
+      userId: 'user-2', teamId: 'team-1', role: 'MEMBER',
+    } as never);
+
+    await addTeamMember('team-1', 'user-2');
+
+    expect(vi.mocked(prisma.teamMember.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { teamId: 'team-1', userId: 'user-2', role: 'MEMBER' } })
+    );
+  });
+
+  it('creates member with specified role', async () => {
+    vi.mocked(prisma.teamMember.findUnique).mockResolvedValueOnce(null);
+    vi.mocked(prisma.teamMember.create).mockResolvedValueOnce({} as never);
+
+    await addTeamMember('team-1', 'user-3', 'ADMIN');
+
+    expect(vi.mocked(prisma.teamMember.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ role: 'ADMIN' }) })
+    );
+  });
+});
+
+// ── getTeamMemberIdsForAdminTeams ──────────────────────────────────────────
+
+describe('getTeamMemberIdsForAdminTeams', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns empty array when user is not admin of any team', async () => {
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([]);
+
+    const result = await getTeamMemberIdsForAdminTeams('user-1');
+
+    expect(result).toEqual([]);
+    // Should not query members when no admin teams
+    expect(vi.mocked(prisma.teamMember.findMany)).toHaveBeenCalledTimes(1);
+  });
+
+  it('returns deduplicated member IDs across admin teams', async () => {
+    // First call: get admin teams
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([{ teamId: 'team-1' }, { teamId: 'team-2' }] as never)
+      // Second call: get members of those teams
+      .mockResolvedValueOnce([{ userId: 'user-2' }, { userId: 'user-3' }] as never);
+
+    const result = await getTeamMemberIdsForAdminTeams('user-1');
+
+    expect(vi.mocked(prisma.teamMember.findMany)).toHaveBeenCalledTimes(2);
+    expect(result).toEqual(['user-2', 'user-3']);
+  });
+
+  it('queries members excluding the admin user themselves', async () => {
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([{ teamId: 'team-1' }] as never)
+      .mockResolvedValueOnce([{ userId: 'user-2' }] as never);
+
+    await getTeamMemberIdsForAdminTeams('admin-user');
+
+    expect(vi.mocked(prisma.teamMember.findMany)).toHaveBeenNthCalledWith(
+      2,
+      expect.objectContaining({ where: expect.objectContaining({ userId: { not: 'admin-user' } }) })
+    );
+  });
+});
+
+// ── isAdminOfUser ──────────────────────────────────────────────────────────
+
+describe('isAdminOfUser', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns false when ownerUserId equals adminUserId', async () => {
+    const result = await isAdminOfUser('same-user', 'same-user');
+    expect(result).toBe(false);
+    expect(vi.mocked(prisma.teamMember.findMany)).not.toHaveBeenCalled();
+  });
+
+  it('returns true when adminUser is admin of a team containing ownerUser', async () => {
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([{ teamId: 'team-1' }] as never) // admin teams
+      .mockResolvedValueOnce([{ userId: 'owner-user' }] as never); // members
+
+    const result = await isAdminOfUser('owner-user', 'admin-user');
+    expect(result).toBe(true);
+  });
+
+  it('returns false when adminUser is not in same team as ownerUser', async () => {
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([{ teamId: 'team-1' }] as never)
+      .mockResolvedValueOnce([{ userId: 'other-user' }] as never); // different members
+
+    const result = await isAdminOfUser('owner-user', 'admin-user');
+    expect(result).toBe(false);
+  });
+
+  it('returns false when admin has no admin teams', async () => {
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([]);
+
+    const result = await isAdminOfUser('owner-user', 'admin-user');
+    expect(result).toBe(false);
+  });
+});
+
+// ── getUserTeams ───────────────────────────────────────────────────────────
+
+describe('getUserTeams', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('transforms result to include userRole and userOkrCount', async () => {
+    const mockMembership = {
+      role: 'ADMIN',
+      _count: { okrs: 3 },
+      team: {
+        id: 'team-1',
+        name: 'Alpha',
+        description: null,
+        members: [],
+        _count: { members: 5 },
+      },
+    };
+
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([mockMembership] as never);
+
+    const result = await getUserTeams('user-1');
+
+    expect(result).toHaveLength(1);
+    expect(result[0]).toMatchObject({
+      id: 'team-1',
+      name: 'Alpha',
+      userRole: 'ADMIN',
+      userOkrCount: 3,
+    });
+  });
+
+  it('returns empty array when user is in no teams', async () => {
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([]);
+    const result = await getUserTeams('user-1');
+    expect(result).toEqual([]);
+  });
+
+  it('spreads team properties into the result', async () => {
+    const mockMembership = {
+      role: 'MEMBER',
+      _count: { okrs: 0 },
+      team: {
+        id: 'team-2',
+        name: 'Beta',
+        description: 'A team',
+        members: [{ id: 'm-1' }],
+        _count: { members: 1 },
+      },
+    };
+
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([mockMembership] as never);
+
+    const result = await getUserTeams('user-2');
+
+    expect(result[0]).toMatchObject({
+      id: 'team-2',
+      description: 'A team',
+      userRole: 'MEMBER',
+      userOkrCount: 0,
+    });
+  });
+});
diff --git a/src/services/__tests__/weather.test.ts b/src/services/__tests__/weather.test.ts
new file mode 100644
index 0000000..2dae717
--- /dev/null
+++ b/src/services/__tests__/weather.test.ts
@@ -0,0 +1,279 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import {
+  getPreviousWeatherEntriesForUsers,
+  shareWeatherSessionToTeam,
+  getWeatherSessionsHistory,
+} from '@/services/weather';
+
+vi.mock('@/services/database', () => ({
+  prisma: {
+    weatherEntry: {
+      findMany: vi.fn(),
+    },
+    weatherSession: {
+      findFirst: vi.fn(),
+      findMany: vi.fn(),
+      count: vi.fn(),
+    },
+    weatherSessionShare: {
+      findMany: vi.fn(),
+      upsert: vi.fn(),
+    },
+    teamMember: {
+      findMany: vi.fn(),
+    },
+  },
+}));
+
+// teams service is imported by weather.ts
+vi.mock('@/services/teams', () => ({
+  getTeamMemberIdsForAdminTeams: vi.fn(),
+}));
+
+// session-permissions and session-share-events are module-level side effects
+vi.mock('@/services/session-permissions', () => ({
+  createSessionPermissionChecks: () => ({
+    canAccess: vi.fn().mockResolvedValue(true),
+    canEdit: vi.fn().mockResolvedValue(true),
+    canDelete: vi.fn().mockResolvedValue(true),
+  }),
+}));
+
+vi.mock('@/services/session-share-events', () => ({
+  createShareAndEventHandlers: () => ({
+    share: vi.fn(),
+    removeShare: vi.fn(),
+    getShares: vi.fn(),
+    createEvent: vi.fn(),
+    getEvents: vi.fn(),
+    getLatestEventTimestamp: vi.fn(),
+  }),
+}));
+
+vi.mock('@/services/session-queries', () => ({
+  mergeSessionsByUserId: vi.fn(),
+  fetchTeamCollaboratorSessions: vi.fn(),
+  getSessionByIdGeneric: vi.fn(),
+}));
+
+const { prisma } = await import('@/services/database');
+
+// ── getPreviousWeatherEntriesForUsers ──────────────────────────────────────
+
+describe('getPreviousWeatherEntriesForUsers', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns empty map when userIds is empty', async () => {
+    const result = await getPreviousWeatherEntriesForUsers('s-1', new Date(), []);
+    expect(result.size).toBe(0);
+    expect(vi.mocked(prisma.weatherEntry.findMany)).not.toHaveBeenCalled();
+  });
+
+  it('returns one entry per user using most recent values', async () => {
+    const olderDate = new Date('2026-01-01');
+    const newerDate = new Date('2026-01-08');
+
+    vi.mocked(prisma.weatherEntry.findMany).mockResolvedValueOnce([
+      { userId: 'u1', performanceEmoji: '☀️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null, session: { date: newerDate } },
+      { userId: 'u1', performanceEmoji: '🌧️', moralEmoji: '☀️', fluxEmoji: null, valueCreationEmoji: null, session: { date: olderDate } },
+    ] as never);
+
+    const result = await getPreviousWeatherEntriesForUsers('current-session', new Date(), ['u1']);
+
+    const entry = result.get('u1');
+    // Most recent entry (newerDate) wins for performanceEmoji
+    expect(entry?.performanceEmoji).toBe('☀️');
+    // Falls back to older entry for moralEmoji (newer was null)
+    expect(entry?.moralEmoji).toBe('☀️');
+  });
+
+  it('uses per-axis fallback when latest entry has null values', async () => {
+    const older = new Date('2026-01-01');
+    const newer = new Date('2026-01-08');
+
+    vi.mocked(prisma.weatherEntry.findMany).mockResolvedValueOnce([
+      // Newer: has performance but not moral
+      { userId: 'u1', performanceEmoji: '☁️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null, session: { date: newer } },
+      // Older: has moral but not performance
+      { userId: 'u1', performanceEmoji: null, moralEmoji: '🌤️', fluxEmoji: null, valueCreationEmoji: null, session: { date: older } },
+    ] as never);
+
+    const result = await getPreviousWeatherEntriesForUsers('s-1', new Date(), ['u1']);
+    const entry = result.get('u1');
+
+    expect(entry?.performanceEmoji).toBe('☁️'); // from newer
+    expect(entry?.moralEmoji).toBe('🌤️');       // fallback from older
+  });
+
+  it('handles multiple users independently', async () => {
+    const date = new Date('2026-01-01');
+    vi.mocked(prisma.weatherEntry.findMany).mockResolvedValueOnce([
+      { userId: 'u1', performanceEmoji: '☀️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null, session: { date } },
+      { userId: 'u2', performanceEmoji: '🌧️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null, session: { date } },
+    ] as never);
+
+    const result = await getPreviousWeatherEntriesForUsers('s-1', new Date(), ['u1', 'u2']);
+
+    expect(result.get('u1')?.performanceEmoji).toBe('☀️');
+    expect(result.get('u2')?.performanceEmoji).toBe('🌧️');
+  });
+
+  it('returns null for all axes when no previous entries for a user', async () => {
+    vi.mocked(prisma.weatherEntry.findMany).mockResolvedValueOnce([]);
+    const result = await getPreviousWeatherEntriesForUsers('s-1', new Date(), ['u1']);
+    // No entries returned, map is empty
+    expect(result.get('u1')).toBeUndefined();
+  });
+});
+
+// ── shareWeatherSessionToTeam ──────────────────────────────────────────────
+
+describe('shareWeatherSessionToTeam', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('throws when session not found or not owned', async () => {
+    vi.mocked(prisma.weatherSession.findFirst).mockResolvedValueOnce(null);
+
+    await expect(shareWeatherSessionToTeam('s-1', 'owner-1', 'team-1')).rejects.toThrow(
+      'Session not found or not owned'
+    );
+  });
+
+  it('throws when another weather session exists for same team this week', async () => {
+    const sessionDate = new Date('2026-03-10');
+    vi.mocked(prisma.weatherSession.findFirst).mockResolvedValueOnce({ id: 's-1', date: sessionDate } as never);
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([{ userId: 'u2' }, { userId: 'u3' }] as never); // count check
+    vi.mocked(prisma.weatherSession.count).mockResolvedValueOnce(1); // existing session this week
+
+    await expect(shareWeatherSessionToTeam('s-1', 'owner-1', 'team-1')).rejects.toThrow(
+      'déjà une météo pour cette semaine'
+    );
+  });
+
+  it('throws when team has no members', async () => {
+    const sessionDate = new Date('2026-03-10');
+    vi.mocked(prisma.weatherSession.findFirst).mockResolvedValueOnce({ id: 's-1', date: sessionDate } as never);
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([]) // no members for count check → skip week check
+      .mockResolvedValueOnce([]); // no full members either
+
+    await expect(shareWeatherSessionToTeam('s-1', 'owner-1', 'team-1')).rejects.toThrow(
+      'Team has no members'
+    );
+  });
+
+  it('shares session with all team members except owner', async () => {
+    const sessionDate = new Date('2026-03-10');
+    vi.mocked(prisma.weatherSession.findFirst).mockResolvedValueOnce({ id: 's-1', date: sessionDate } as never);
+    // First findMany: team member IDs for week check (empty → skips count check)
+    vi.mocked(prisma.teamMember.findMany)
+      .mockResolvedValueOnce([]) // empty for week-check path
+      .mockResolvedValueOnce([
+        { userId: 'owner-1', user: { id: 'owner-1', name: 'Owner', email: 'o@ex.com' } },
+        { userId: 'member-1', user: { id: 'member-1', name: 'Member', email: 'm@ex.com' } },
+        { userId: 'member-2', user: { id: 'member-2', name: 'Member2', email: 'm2@ex.com' } },
+      ] as never); // full members
+    vi.mocked(prisma.weatherSessionShare.upsert).mockResolvedValue({ role: 'EDITOR', user: {} } as never);
+
+    await shareWeatherSessionToTeam('s-1', 'owner-1', 'team-1');
+
+    // Should call upsert for member-1 and member-2 (not owner-1)
+    expect(vi.mocked(prisma.weatherSessionShare.upsert)).toHaveBeenCalledTimes(2);
+    const calls = vi.mocked(prisma.weatherSessionShare.upsert).mock.calls;
+    const sharedUserIds = calls.map((c) => c[0].create.userId);
+    expect(sharedUserIds).toContain('member-1');
+    expect(sharedUserIds).toContain('member-2');
+    expect(sharedUserIds).not.toContain('owner-1');
+  });
+});
+
+// ── getWeatherSessionsHistory ──────────────────────────────────────────────
+
+describe('getWeatherSessionsHistory', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('returns sorted history by date ascending', async () => {
+    const older = new Date('2026-01-01');
+    const newer = new Date('2026-02-01');
+
+    vi.mocked(prisma.weatherSession.findMany).mockResolvedValueOnce([
+      { id: 's-2', title: 'Session 2', date: newer, entries: [] },
+      { id: 's-1', title: 'Session 1', date: older, entries: [] },
+    ] as never);
+    vi.mocked(prisma.weatherSessionShare.findMany).mockResolvedValueOnce([]);
+
+    const result = await getWeatherSessionsHistory('user-1');
+
+    expect(result[0].sessionId).toBe('s-1');
+    expect(result[1].sessionId).toBe('s-2');
+  });
+
+  it('deduplicates sessions appearing in both own and shared', async () => {
+    const date = new Date('2026-01-01');
+    vi.mocked(prisma.weatherSession.findMany).mockResolvedValueOnce([
+      { id: 's-1', title: 'Session', date, entries: [] },
+    ] as never);
+    vi.mocked(prisma.weatherSessionShare.findMany).mockResolvedValueOnce([
+      { session: { id: 's-1', title: 'Session', date, entries: [] } },
+    ] as never);
+
+    const result = await getWeatherSessionsHistory('user-1');
+
+    expect(result).toHaveLength(1);
+  });
+
+  it('calculates average scores from entries using emoji → number mapping', async () => {
+    const date = new Date('2026-01-01');
+    // '☀️' is index 1 in WEATHER_EMOJIS, '🌤️' is index 2
+    vi.mocked(prisma.weatherSession.findMany).mockResolvedValueOnce([
+      {
+        id: 's-1',
+        title: 'Session',
+        date,
+        entries: [
+          { performanceEmoji: '☀️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null },
+          { performanceEmoji: '🌤️', moralEmoji: null, fluxEmoji: null, valueCreationEmoji: null },
+        ],
+      },
+    ] as never);
+    vi.mocked(prisma.weatherSessionShare.findMany).mockResolvedValueOnce([]);
+
+    const result = await getWeatherSessionsHistory('user-1');
+
+    // avgScore(['☀️', '🌤️']) = (1 + 2) / 2 = 1.5
+    expect(result[0].performance).toBe(1.5);
+    expect(result[0].moral).toBeNull(); // all null → null
+  });
+
+  it('returns null score when no entries have that axis', async () => {
+    const date = new Date('2026-01-01');
+    vi.mocked(prisma.weatherSession.findMany).mockResolvedValueOnce([
+      { id: 's-1', title: 'Session', date, entries: [] },
+    ] as never);
+    vi.mocked(prisma.weatherSessionShare.findMany).mockResolvedValueOnce([]);
+
+    const result = await getWeatherSessionsHistory('user-1');
+
+    expect(result[0].performance).toBeNull();
+    expect(result[0].moral).toBeNull();
+    expect(result[0].flux).toBeNull();
+    expect(result[0].valueCreation).toBeNull();
+  });
+
+  it('includes both own and shared sessions', async () => {
+    vi.mocked(prisma.weatherSession.findMany).mockResolvedValueOnce([
+      { id: 's-own', title: 'Own', date: new Date('2026-01-01'), entries: [] },
+    ] as never);
+    vi.mocked(prisma.weatherSessionShare.findMany).mockResolvedValueOnce([
+      { session: { id: 's-shared', title: 'Shared', date: new Date('2026-02-01'), entries: [] } },
+    ] as never);
+
+    const result = await getWeatherSessionsHistory('user-1');
+
+    expect(result).toHaveLength(2);
+    const ids = result.map((r) => r.sessionId);
+    expect(ids).toContain('s-own');
+    expect(ids).toContain('s-shared');
+  });
+});
diff --git a/src/services/__tests__/workshops.test.ts b/src/services/__tests__/workshops.test.ts
new file mode 100644
index 0000000..ba4fe86
--- /dev/null
+++ b/src/services/__tests__/workshops.test.ts
@@ -0,0 +1,511 @@
+/**
+ * Workshop-specific business logic tests:
+ * - sessions.ts: createSwotItem, duplicateSwotItem, updateAction
+ * - moving-motivators.ts: createMotivatorSession, updateCardInfluence
+ * - gif-mood.ts: addGifMoodItem, shareGifMoodSessionToTeam
+ * - session-share-events.ts: getLatestEventTimestamp, cleanupOldEvents
+ */
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+
+// ── Shared mocks ────────────────────────────────────────────────────────────
+
+vi.mock('@/services/database', () => ({
+  prisma: {
+    swotItem: {
+      aggregate: vi.fn(),
+      create: vi.fn(),
+      findUnique: vi.fn(),
+    },
+    actionLink: {
+      deleteMany: vi.fn(),
+      createMany: vi.fn(),
+    },
+    action: {
+      update: vi.fn(),
+    },
+    movingMotivatorsSession: {
+      create: vi.fn(),
+    },
+    motivatorCard: {
+      update: vi.fn(),
+    },
+    gifMoodItem: {
+      count: vi.fn(),
+      create: vi.fn(),
+    },
+    gifMoodSession: {
+      findFirst: vi.fn(),
+    },
+    gMSessionShare: {
+      upsert: vi.fn(),
+    },
+    teamMember: {
+      findMany: vi.fn(),
+    },
+  },
+}));
+
+vi.mock('@/services/auth', () => ({
+  resolveCollaborator: vi.fn(),
+  batchResolveCollaborators: vi.fn().mockResolvedValue(new Map()),
+}));
+
+vi.mock('@/services/teams', () => ({
+  getTeamMemberIdsForAdminTeams: vi.fn(),
+}));
+
+vi.mock('@/services/session-permissions', () => ({
+  createSessionPermissionChecks: () => ({
+    canAccess: vi.fn().mockResolvedValue(true),
+    canEdit: vi.fn().mockResolvedValue(true),
+    canDelete: vi.fn().mockResolvedValue(true),
+  }),
+}));
+
+vi.mock('@/services/session-share-events', () => ({
+  createShareAndEventHandlers: () => ({
+    share: vi.fn(),
+    removeShare: vi.fn(),
+    getShares: vi.fn(),
+    createEvent: vi.fn(),
+    getEvents: vi.fn(),
+    getLatestEventTimestamp: vi.fn(),
+  }),
+}));
+
+vi.mock('@/services/session-queries', () => ({
+  mergeSessionsByUserId: vi.fn().mockResolvedValue([]),
+  fetchTeamCollaboratorSessions: vi.fn().mockResolvedValue([]),
+  getSessionByIdGeneric: vi.fn(),
+}));
+
+const { prisma } = await import('@/services/database');
+
+// ── sessions.ts: createSwotItem ──────────────────────────────────────────
+
+import { createSwotItem, duplicateSwotItem, updateAction } from '@/services/sessions';
+
+describe('createSwotItem', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('uses maxOrder + 1 for the new item order', async () => {
+    vi.mocked(prisma.swotItem.aggregate).mockResolvedValueOnce({ _max: { order: 3 } } as never);
+    vi.mocked(prisma.swotItem.create).mockResolvedValueOnce({ id: 'item-1', order: 4 } as never);
+
+    await createSwotItem('session-1', { content: 'New item', category: 'STRENGTH' });
+
+    expect(vi.mocked(prisma.swotItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ order: 4 }) })
+    );
+  });
+
+  it('uses order 0 when no items exist yet', async () => {
+    vi.mocked(prisma.swotItem.aggregate).mockResolvedValueOnce({ _max: { order: null } } as never);
+    vi.mocked(prisma.swotItem.create).mockResolvedValueOnce({ id: 'item-1', order: 0 } as never);
+
+    await createSwotItem('session-1', { content: 'First item', category: 'WEAKNESS' });
+
+    expect(vi.mocked(prisma.swotItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ order: 0 }) })
+    );
+  });
+
+  it('queries aggregate for the correct session and category', async () => {
+    vi.mocked(prisma.swotItem.aggregate).mockResolvedValueOnce({ _max: { order: null } } as never);
+    vi.mocked(prisma.swotItem.create).mockResolvedValueOnce({} as never);
+
+    await createSwotItem('session-42', { content: 'Item', category: 'OPPORTUNITY' });
+
+    expect(vi.mocked(prisma.swotItem.aggregate)).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { sessionId: 'session-42', category: 'OPPORTUNITY' } })
+    );
+  });
+});
+
+// ── sessions.ts: duplicateSwotItem ────────────────────────────────────────
+
+describe('duplicateSwotItem', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('throws when original item not found', async () => {
+    vi.mocked(prisma.swotItem.findUnique).mockResolvedValueOnce(null);
+
+    await expect(duplicateSwotItem('item-999')).rejects.toThrow('Item not found');
+  });
+
+  it('creates copy with recalculated order (maxOrder + 1)', async () => {
+    const original = { id: 'item-1', content: 'Original', category: 'STRENGTH', sessionId: 'session-1' };
+    vi.mocked(prisma.swotItem.findUnique).mockResolvedValueOnce(original as never);
+    vi.mocked(prisma.swotItem.aggregate).mockResolvedValueOnce({ _max: { order: 5 } } as never);
+    vi.mocked(prisma.swotItem.create).mockResolvedValueOnce({ id: 'item-2', order: 6 } as never);
+
+    await duplicateSwotItem('item-1');
+
+    expect(vi.mocked(prisma.swotItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({
+        data: {
+          content: 'Original',
+          category: 'STRENGTH',
+          sessionId: 'session-1',
+          order: 6,
+        },
+      })
+    );
+  });
+
+  it('uses order 0 when category has no existing items', async () => {
+    const original = { id: 'item-1', content: 'Item', category: 'THREAT', sessionId: 's-1' };
+    vi.mocked(prisma.swotItem.findUnique).mockResolvedValueOnce(original as never);
+    vi.mocked(prisma.swotItem.aggregate).mockResolvedValueOnce({ _max: { order: null } } as never);
+    vi.mocked(prisma.swotItem.create).mockResolvedValueOnce({ id: 'item-2', order: 0 } as never);
+
+    await duplicateSwotItem('item-1');
+
+    expect(vi.mocked(prisma.swotItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ order: 0 }) })
+    );
+  });
+});
+
+// ── sessions.ts: updateAction ─────────────────────────────────────────────
+
+describe('updateAction', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('does not touch links when linkedItemIds is not provided', async () => {
+    vi.mocked(prisma.action.update).mockResolvedValueOnce({ id: 'a-1', links: [] } as never);
+
+    await updateAction('a-1', { title: 'Updated title' });
+
+    expect(vi.mocked(prisma.actionLink.deleteMany)).not.toHaveBeenCalled();
+    expect(vi.mocked(prisma.actionLink.createMany)).not.toHaveBeenCalled();
+  });
+
+  it('deletes all existing links and recreates when linkedItemIds is provided', async () => {
+    vi.mocked(prisma.actionLink.deleteMany).mockResolvedValueOnce({ count: 2 } as never);
+    vi.mocked(prisma.actionLink.createMany).mockResolvedValueOnce({ count: 2 } as never);
+    vi.mocked(prisma.action.update).mockResolvedValueOnce({ id: 'a-1', links: [] } as never);
+
+    await updateAction('a-1', { linkedItemIds: ['item-1', 'item-2'] });
+
+    expect(vi.mocked(prisma.actionLink.deleteMany)).toHaveBeenCalledWith(
+      expect.objectContaining({ where: { actionId: 'a-1' } })
+    );
+    expect(vi.mocked(prisma.actionLink.createMany)).toHaveBeenCalledWith({
+      data: [
+        { actionId: 'a-1', swotItemId: 'item-1' },
+        { actionId: 'a-1', swotItemId: 'item-2' },
+      ],
+    });
+  });
+
+  it('deletes links but skips createMany when linkedItemIds is empty', async () => {
+    vi.mocked(prisma.actionLink.deleteMany).mockResolvedValueOnce({ count: 1 } as never);
+    vi.mocked(prisma.action.update).mockResolvedValueOnce({ id: 'a-1', links: [] } as never);
+
+    await updateAction('a-1', { linkedItemIds: [] });
+
+    expect(vi.mocked(prisma.actionLink.deleteMany)).toHaveBeenCalled();
+    expect(vi.mocked(prisma.actionLink.createMany)).not.toHaveBeenCalled();
+  });
+});
+
+// ── moving-motivators.ts: createMotivatorSession ──────────────────────────
+
+import { createMotivatorSession, updateCardInfluence } from '@/services/moving-motivators';
+
+describe('createMotivatorSession', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('creates session with exactly 10 motivator cards', async () => {
+    vi.mocked(prisma.movingMotivatorsSession.create).mockResolvedValueOnce({
+      id: 'session-1',
+      cards: new Array(10).fill({ id: 'c', type: 'STATUS', orderIndex: 1, influence: 0 }),
+    } as never);
+
+    await createMotivatorSession('user-1', { title: 'Test', participant: 'Alice' });
+
+    const call = vi.mocked(prisma.movingMotivatorsSession.create).mock.calls[0][0];
+    expect(call.data.cards.create).toHaveLength(10);
+  });
+
+  it('initializes all cards with influence 0 and correct orderIndex (1-based)', async () => {
+    vi.mocked(prisma.movingMotivatorsSession.create).mockResolvedValueOnce({ id: 's-1', cards: [] } as never);
+
+    await createMotivatorSession('user-1', { title: 'Test', participant: 'Alice' });
+
+    const call = vi.mocked(prisma.movingMotivatorsSession.create).mock.calls[0][0];
+    const cards = call.data.cards.create;
+
+    expect(cards[0]).toMatchObject({ influence: 0, orderIndex: 1 });
+    expect(cards[9]).toMatchObject({ influence: 0, orderIndex: 10 });
+  });
+
+  it('includes all 10 motivator types', async () => {
+    vi.mocked(prisma.movingMotivatorsSession.create).mockResolvedValueOnce({ id: 's-1', cards: [] } as never);
+
+    await createMotivatorSession('user-1', { title: 'T', participant: 'B' });
+
+    const call = vi.mocked(prisma.movingMotivatorsSession.create).mock.calls[0][0];
+    const types = call.data.cards.create.map((c: { type: string }) => c.type);
+
+    expect(types).toContain('STATUS');
+    expect(types).toContain('PURPOSE');
+    expect(types).toContain('CURIOSITY');
+    expect(types).toContain('FREEDOM');
+    expect(new Set(types).size).toBe(10);
+  });
+});
+
+// ── moving-motivators.ts: updateCardInfluence ─────────────────────────────
+
+describe('updateCardInfluence', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('passes influence value as-is when within bounds', async () => {
+    vi.mocked(prisma.motivatorCard.update).mockResolvedValueOnce({ id: 'c-1', influence: 2 } as never);
+
+    await updateCardInfluence('c-1', 2);
+
+    expect(vi.mocked(prisma.motivatorCard.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { influence: 2 } })
+    );
+  });
+
+  it('clamps influence to -3 when below minimum', async () => {
+    vi.mocked(prisma.motivatorCard.update).mockResolvedValueOnce({ id: 'c-1', influence: -3 } as never);
+
+    await updateCardInfluence('c-1', -10);
+
+    expect(vi.mocked(prisma.motivatorCard.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { influence: -3 } })
+    );
+  });
+
+  it('clamps influence to +3 when above maximum', async () => {
+    vi.mocked(prisma.motivatorCard.update).mockResolvedValueOnce({ id: 'c-1', influence: 3 } as never);
+
+    await updateCardInfluence('c-1', 99);
+
+    expect(vi.mocked(prisma.motivatorCard.update)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: { influence: 3 } })
+    );
+  });
+
+  it('allows exact boundary values -3 and +3', async () => {
+    vi.mocked(prisma.motivatorCard.update).mockResolvedValue({ id: 'c-1', influence: -3 } as never);
+
+    await updateCardInfluence('c-1', -3);
+    await updateCardInfluence('c-1', 3);
+
+    const calls = vi.mocked(prisma.motivatorCard.update).mock.calls;
+    expect(calls[0][0].data.influence).toBe(-3);
+    expect(calls[1][0].data.influence).toBe(3);
+  });
+});
+
+// ── gif-mood.ts: addGifMoodItem ────────────────────────────────────────────
+
+import { addGifMoodItem, shareGifMoodSessionToTeam } from '@/services/gif-mood';
+
+describe('addGifMoodItem', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('throws when user has reached GIF_MOOD_MAX_ITEMS limit (5)', async () => {
+    vi.mocked(prisma.gifMoodItem.count).mockResolvedValueOnce(5);
+
+    await expect(addGifMoodItem('session-1', 'user-1', { gifUrl: 'https://example.com/gif.gif' }))
+      .rejects.toThrow('Maximum 5');
+  });
+
+  it('creates item with order set to current count (append at end)', async () => {
+    vi.mocked(prisma.gifMoodItem.count).mockResolvedValueOnce(2);
+    vi.mocked(prisma.gifMoodItem.create).mockResolvedValueOnce({ id: 'gif-1', order: 2 } as never);
+
+    await addGifMoodItem('session-1', 'user-1', { gifUrl: 'https://example.com/gif.gif' });
+
+    expect(vi.mocked(prisma.gifMoodItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ order: 2 }) })
+    );
+  });
+
+  it('allows adding when count is below limit', async () => {
+    vi.mocked(prisma.gifMoodItem.count).mockResolvedValueOnce(4);
+    vi.mocked(prisma.gifMoodItem.create).mockResolvedValueOnce({ id: 'gif-1' } as never);
+
+    await expect(addGifMoodItem('s-1', 'u-1', { gifUrl: 'url', note: 'hello' })).resolves.not.toThrow();
+
+    expect(vi.mocked(prisma.gifMoodItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ note: 'hello' }) })
+    );
+  });
+
+  it('sets note to null when not provided', async () => {
+    vi.mocked(prisma.gifMoodItem.count).mockResolvedValueOnce(0);
+    vi.mocked(prisma.gifMoodItem.create).mockResolvedValueOnce({ id: 'gif-1' } as never);
+
+    await addGifMoodItem('s-1', 'u-1', { gifUrl: 'url' });
+
+    expect(vi.mocked(prisma.gifMoodItem.create)).toHaveBeenCalledWith(
+      expect.objectContaining({ data: expect.objectContaining({ note: null }) })
+    );
+  });
+});
+
+// ── gif-mood.ts: shareGifMoodSessionToTeam ────────────────────────────────
+
+describe('shareGifMoodSessionToTeam', () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it('throws when session not found or not owned', async () => {
+    vi.mocked(prisma.gifMoodSession.findFirst).mockResolvedValueOnce(null);
+
+    await expect(shareGifMoodSessionToTeam('s-1', 'owner-1', 'team-1')).rejects.toThrow(
+      'Session not found or not owned'
+    );
+  });
+
+  it('throws when team has no members', async () => {
+    vi.mocked(prisma.gifMoodSession.findFirst).mockResolvedValueOnce({ id: 's-1' } as never);
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([]);
+
+    await expect(shareGifMoodSessionToTeam('s-1', 'owner-1', 'team-1')).rejects.toThrow(
+      'Team has no members'
+    );
+  });
+
+  it('shares with all team members except owner', async () => {
+    vi.mocked(prisma.gifMoodSession.findFirst).mockResolvedValueOnce({ id: 's-1' } as never);
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([
+      { userId: 'owner-1', user: { id: 'owner-1', name: 'Owner', email: 'o@ex.com' } },
+      { userId: 'member-1', user: { id: 'member-1', name: 'Member', email: 'm@ex.com' } },
+    ] as never);
+    vi.mocked(prisma.gMSessionShare.upsert).mockResolvedValue({ role: 'EDITOR', user: {} } as never);
+
+    await shareGifMoodSessionToTeam('s-1', 'owner-1', 'team-1');
+
+    // Only member-1 gets shared (not owner-1)
+    expect(vi.mocked(prisma.gMSessionShare.upsert)).toHaveBeenCalledTimes(1);
+    expect(vi.mocked(prisma.gMSessionShare.upsert)).toHaveBeenCalledWith(
+      expect.objectContaining({ create: expect.objectContaining({ userId: 'member-1' }) })
+    );
+  });
+
+  it('uses EDITOR role by default', async () => {
+    vi.mocked(prisma.gifMoodSession.findFirst).mockResolvedValueOnce({ id: 's-1' } as never);
+    vi.mocked(prisma.teamMember.findMany).mockResolvedValueOnce([
+      { userId: 'member-1', user: { id: 'member-1', name: 'M', email: 'm@ex.com' } },
+    ] as never);
+    vi.mocked(prisma.gMSessionShare.upsert).mockResolvedValue({ role: 'EDITOR', user: {} } as never);
+
+    await shareGifMoodSessionToTeam('s-1', 'different-owner', 'team-1');
+
+    expect(vi.mocked(prisma.gMSessionShare.upsert)).toHaveBeenCalledWith(
+      expect.objectContaining({ create: expect.objectContaining({ role: 'EDITOR' }) })
+    );
+  });
+});
+
+// ── session-share-events.ts: getLatestEventTimestamp & cleanupOldEvents ──────
+
+// Use the real implementation (not the mock above which is for internal service use)
+const { createShareAndEventHandlers } = await vi.importActual<
+  typeof import('@/services/session-share-events')
+>('@/services/session-share-events');
+
+describe('getLatestEventTimestamp', () => {
+  it('returns the createdAt of the most recent event', async () => {
+    const ts = new Date('2026-03-10T10:00:00Z');
+    const eventModel = {
+      create: vi.fn(),
+      findMany: vi.fn(),
+      findFirst: vi.fn().mockResolvedValueOnce({ createdAt: ts }),
+      deleteMany: vi.fn(),
+    };
+    const { getLatestEventTimestamp } = createShareAndEventHandlers(
+      { findFirst: vi.fn() },
+      { upsert: vi.fn(), deleteMany: vi.fn(), findMany: vi.fn() },
+      eventModel,
+      vi.fn()
+    );
+
+    const result = await getLatestEventTimestamp('session-1');
+    expect(result).toEqual(ts);
+  });
+
+  it('returns undefined when no events exist', async () => {
+    const eventModel = {
+      create: vi.fn(),
+      findMany: vi.fn(),
+      findFirst: vi.fn().mockResolvedValueOnce(null),
+      deleteMany: vi.fn(),
+    };
+    const { getLatestEventTimestamp } = createShareAndEventHandlers(
+      { findFirst: vi.fn() },
+      { upsert: vi.fn(), deleteMany: vi.fn(), findMany: vi.fn() },
+      eventModel,
+      vi.fn()
+    );
+
+    const result = await getLatestEventTimestamp('session-1');
+    expect(result).toBeUndefined();
+  });
+});
+
+describe('cleanupOldEvents', () => {
+  it('deletes events older than 24 hours by default', async () => {
+    const deleteMany = vi.fn().mockResolvedValueOnce({ count: 5 });
+    const eventModel = { create: vi.fn(), findMany: vi.fn(), findFirst: vi.fn(), deleteMany };
+    const { cleanupOldEvents } = createShareAndEventHandlers(
+      { findFirst: vi.fn() },
+      { upsert: vi.fn(), deleteMany: vi.fn(), findMany: vi.fn() },
+      eventModel,
+      vi.fn()
+    );
+
+    const before = Date.now();
+    await cleanupOldEvents();
+    const after = Date.now();
+
+    const cutoff: Date = deleteMany.mock.calls[0][0].where.createdAt.lt;
+    expect(cutoff.getTime()).toBeGreaterThanOrEqual(before - 24 * 60 * 60 * 1000 - 100);
+    expect(cutoff.getTime()).toBeLessThanOrEqual(after - 24 * 60 * 60 * 1000 + 100);
+  });
+
+  it('deletes events older than custom maxAgeHours', async () => {
+    const deleteMany = vi.fn().mockResolvedValueOnce({ count: 0 });
+    const eventModel = { create: vi.fn(), findMany: vi.fn(), findFirst: vi.fn(), deleteMany };
+    const { cleanupOldEvents } = createShareAndEventHandlers(
+      { findFirst: vi.fn() },
+      { upsert: vi.fn(), deleteMany: vi.fn(), findMany: vi.fn() },
+      eventModel,
+      vi.fn()
+    );
+
+    const before = Date.now();
+    await cleanupOldEvents(1); // 1 hour
+    const after = Date.now();
+
+    const cutoff: Date = deleteMany.mock.calls[0][0].where.createdAt.lt;
+    expect(cutoff.getTime()).toBeGreaterThanOrEqual(before - 60 * 60 * 1000 - 100);
+    expect(cutoff.getTime()).toBeLessThanOrEqual(after - 60 * 60 * 1000 + 100);
+  });
+
+  it('returns the count of deleted events', async () => {
+    const eventModel = {
+      create: vi.fn(),
+      findMany: vi.fn(),
+      findFirst: vi.fn(),
+      deleteMany: vi.fn().mockResolvedValueOnce({ count: 42 }),
+    };
+    const { cleanupOldEvents } = createShareAndEventHandlers(
+      { findFirst: vi.fn() },
+      { upsert: vi.fn(), deleteMany: vi.fn(), findMany: vi.fn() },
+      eventModel,
+      vi.fn()
+    );
+
+    const result = await cleanupOldEvents();
+    expect(result).toEqual({ count: 42 });
+  });
+});
diff --git a/vitest.config.ts b/vitest.config.ts
new file mode 100644
index 0000000..a76743a
--- /dev/null
+++ b/vitest.config.ts
@@ -0,0 +1,23 @@
+import { defineConfig } from 'vitest/config';
+import tsconfigPaths from 'vite-tsconfig-paths';
+
+export default defineConfig({
+  plugins: [tsconfigPaths()],
+  test: {
+    environment: 'node',
+    globals: true,
+    coverage: {
+      provider: 'v8',
+      include: ['src/services/**/*.ts', 'src/lib/**/*.ts'],
+      exclude: [
+        'src/services/__tests__/**',
+        'src/lib/__tests__/**',
+        'src/services/database.ts',
+        'src/lib/types.ts',
+        'src/lib/auth.ts',
+        'src/lib/auth.config.ts',
+      ],
+      reporter: ['text', 'html'],
+    },
+  },
+});