From 141ad0acb6add63e3eec58bf9aaaec269ed9fea0 Mon Sep 17 00:00:00 2001
From: Maurice <mauriceboe@icloud.com>
Date: Mon, 12 Oct 2026 21:13:57 +0000
Subject: [PATCH] test(budget): the cases for people who left the trip get a
 suite of their own

---
 .../unit/nest/budget.former-members.test.ts   | 246 ++++++++++++++++++
 .../tests/unit/nest/budget.service.db.test.ts | 162 ------------
 2 files changed, 246 insertions(+), 162 deletions(-)
 create mode 100644 server/tests/unit/nest/budget.former-members.test.ts

diff --git a/server/tests/unit/nest/budget.former-members.test.ts b/server/tests/unit/nest/budget.former-members.test.ts
new file mode 100644
index 000000000..b59aa0b09
--- /dev/null
+++ b/server/tests/unit/nest/budget.former-members.test.ts
@@ -0,0 +1,246 @@
+/**
+ * People who left the trip keep their part of an expense (#2604).
+ * BUDGET-SVC-DB-087 through 094, moved out of budget.service.db.test.ts.
+ *
+ * Real in-memory SQLite over the container: BudgetService and TripMembersService
+ * come out of TripMembersModule, so a member is removed from the trip the way the
+ * app removes one, and the expense saves afterwards run the real roster filter.
+ */
+import { BudgetItemMembers } from '../../../src/db/entities/BudgetItemMembers.entity';
+import { BudgetService } from '../../../src/nest/budget/budget.service';
+import { TripMembersModule } from '../../../src/nest/trip-members/trip-members.module';
+import { TripMembersService } from '../../../src/nest/trip-members/trip-members.service';
+import { createSnapshotTestDb } from '../../helpers/db-mock';
+import { findRow } from '../../helpers/factories/rows';
+import { addTripMember, makeTrip } from '../../helpers/factories/trips';
+import { makeUser } from '../../helpers/factories/users';
+import { createTestModule, type TestModule } from '../../helpers/test-module';
+import { MikroORM } from '@mikro-orm/core';
+
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+
+const db = createSnapshotTestDb();
+let t: TestModule;
+let budget: BudgetService;
+let membersSvc: TripMembersService;
+const orm = () => t.get(MikroORM);
+
+beforeAll(async () => {
+  t = await createTestModule({ db, imports: [TripMembersModule] });
+  budget = t.get(BudgetService);
+  membersSvc = t.get(TripMembersService);
+});
+
+afterAll(async () => {
+  await t.close();
+  db.close();
+});
+
+async function paidFlag(itemId: number, memberId: number): Promise<number | undefined> {
+  const row = await findRow(orm(), BudgetItemMembers, { budgetItem: itemId, user: memberId });
+  return row?.paid;
+}
+
+// ── People who left the trip keep their part of an expense (#2604) ───────────
+// Removing someone from the trip leaves their payer and split rows in place.
+// Saving the expense used to run every id back through the roster filter, so an
+// unchanged save dropped them, total_price shrank to what the rest had paid and
+// a custom split stopped adding up. Ids already on the expense stay allowed; a
+// stranger who never was on it is still dropped (#1952).
+
+describe('someone who left the trip keeps their part of an expense (#2604)', () => {
+  async function tripWithFormerMember() {
+    const { user: alice } = await makeUser(orm());
+    const { user: bob } = await makeUser(orm());
+    const { user: carol } = await makeUser(orm());
+    const trip = await makeTrip(orm(), alice.id);
+    await addTripMember(orm(), trip.id, bob.id);
+    await addTripMember(orm(), trip.id, carol.id);
+    return { alice, bob, carol, trip };
+  }
+  const balanceSum = (balances: { balance: number }[]) => Math.round(balances.reduce((a, b) => a + b.balance, 0) * 100);
+
+  it('BUDGET-SVC-DB-087: an unchanged save keeps a former member as payer and split member', async () => {
+    const { alice, bob, carol, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Rental car',
+      payers: [
+        { user_id: alice.id, amount: 120 },
+        { user_id: bob.id, amount: 60 },
+      ],
+      member_ids: [alice.id, bob.id, carol.id],
+    });
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    // What the expense form sends back: the ids it was seeded with.
+    const saved = await budget.updateBudgetItem(item.id, trip.id, {
+      note: 'keys at the desk',
+      payers: [
+        { user_id: alice.id, amount: 120 },
+        { user_id: bob.id, amount: 60 },
+      ],
+      member_ids: [alice.id, bob.id, carol.id],
+    });
+
+    expect(saved?.total_price).toBe(180);
+    expect(saved?.payers.map((p) => p.user_id).sort()).toEqual([alice.id, bob.id].sort());
+    expect(saved?.members.map((m) => m.user_id).sort()).toEqual([alice.id, bob.id, carol.id].sort());
+    expect(saved?.persons).toBe(3);
+    const settlement = await budget.calculateSettlement(trip.id);
+    expect(balanceSum(settlement.balances)).toBe(0);
+  });
+
+  it('BUDGET-SVC-DB-088: a custom split with a former member still adds up after a save', async () => {
+    const { alice, bob, carol, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Dinner',
+      payers: [{ user_id: bob.id, amount: 90 }],
+      members: [
+        { user_id: alice.id, amount: 30 },
+        { user_id: bob.id, amount: 30 },
+        { user_id: carol.id, amount: 30 },
+      ],
+    });
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    const saved = await budget.updateBudgetItem(item.id, trip.id, {
+      payers: [{ user_id: bob.id, amount: 90 }],
+      members: [
+        { user_id: alice.id, amount: 30 },
+        { user_id: bob.id, amount: 30 },
+        { user_id: carol.id, amount: 30 },
+      ],
+    });
+
+    expect(saved?.total_price).toBe(90);
+    expect(saved?.members.reduce((a, m) => a + (m.amount ?? 0), 0)).toBe(90);
+    const settlement = await budget.calculateSettlement(trip.id);
+    expect(balanceSum(settlement.balances)).toBe(0);
+    expect(settlement.balances.find((b) => b.user_id === bob.id)?.balance).toBe(60);
+  });
+
+  it('BUDGET-SVC-DB-089: a stranger who never was on the expense is still dropped', async () => {
+    const { alice, bob, trip } = await tripWithFormerMember();
+    const { user: outsider } = await makeUser(orm());
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Taxi',
+      payers: [{ user_id: alice.id, amount: 40 }],
+      member_ids: [alice.id, bob.id],
+    });
+
+    const saved = await budget.updateBudgetItem(item.id, trip.id, {
+      payers: [
+        { user_id: alice.id, amount: 40 },
+        { user_id: outsider.id, amount: 10 },
+      ],
+      member_ids: [alice.id, bob.id, outsider.id],
+    });
+
+    expect(saved?.payers.map((p) => p.user_id)).toEqual([alice.id]);
+    expect(saved?.members.map((m) => m.user_id)).not.toContain(outsider.id);
+    expect(saved?.total_price).toBe(40);
+    const viaMembers = await budget.updateMembers(item.id, trip.id, [alice.id, outsider.id]);
+    expect(viaMembers?.members.map((m) => m.user_id)).toEqual([alice.id]);
+  });
+
+  it('BUDGET-SVC-DB-090: leaving a former member out of the save removes them', async () => {
+    const { alice, bob, carol, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Museum',
+      payers: [{ user_id: alice.id, amount: 30 }],
+      member_ids: [alice.id, bob.id, carol.id],
+    });
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    const saved = await budget.updateBudgetItem(item.id, trip.id, {
+      payers: [{ user_id: alice.id, amount: 30 }],
+      member_ids: [alice.id, carol.id],
+    });
+
+    expect(saved?.members.map((m) => m.user_id).sort()).toEqual([alice.id, carol.id].sort());
+    // Once gone from the expense, they cannot be put back while off the trip.
+    const again = await budget.updateBudgetItem(item.id, trip.id, { member_ids: [alice.id, bob.id, carol.id] });
+    expect(again?.members.map((m) => m.user_id)).not.toContain(bob.id);
+  });
+
+  it('BUDGET-SVC-DB-091: a former member who was only in the split can be recorded as the payer', async () => {
+    const { alice, bob, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Tickets',
+      payers: [{ user_id: alice.id, amount: 50 }],
+      member_ids: [alice.id, bob.id],
+    });
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    const saved = await budget.updateBudgetItem(item.id, trip.id, {
+      payers: [{ user_id: bob.id, amount: 50 }],
+      member_ids: [alice.id, bob.id],
+    });
+
+    expect(saved?.payers.map((p) => p.user_id)).toEqual([bob.id]);
+    expect(saved?.total_price).toBe(50);
+  });
+
+  it('BUDGET-SVC-DB-092: the paid ticks survive a form save', async () => {
+    const { alice, bob, carol, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Hotel',
+      payers: [{ user_id: alice.id, amount: 300 }],
+      member_ids: [alice.id, bob.id, carol.id],
+    });
+    await budget.toggleMemberPaid(item.id, trip.id, carol.id, true);
+    await budget.toggleMemberPaid(item.id, trip.id, bob.id, true);
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    await budget.updateBudgetItem(item.id, trip.id, {
+      name: 'Hotel Central',
+      payers: [{ user_id: alice.id, amount: 300 }],
+      member_ids: [alice.id, bob.id, carol.id],
+    });
+
+    expect(await paidFlag(item.id, carol.id)).toBe(1);
+    expect(await paidFlag(item.id, bob.id)).toBe(1);
+    expect(await paidFlag(item.id, alice.id)).toBe(0);
+  });
+
+  it('BUDGET-SVC-DB-093: the payer and member routes keep a former member too', async () => {
+    const { alice, bob, trip } = await tripWithFormerMember();
+    const item = await budget.createBudgetItem(trip.id, {
+      name: 'Ferry',
+      payers: [
+        { user_id: alice.id, amount: 20 },
+        { user_id: bob.id, amount: 20 },
+      ],
+      member_ids: [alice.id, bob.id],
+    });
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    const payers = await budget.setItemPayers(item.id, trip.id, [
+      { user_id: alice.id, amount: 20 },
+      { user_id: bob.id, amount: 20 },
+    ]);
+    expect(payers?.total_price).toBe(40);
+    expect(payers?.payers.map((p) => p.user_id).sort()).toEqual([alice.id, bob.id].sort());
+
+    const members = await budget.updateMembers(item.id, trip.id, [alice.id, bob.id]);
+    expect(members?.members.map((m) => m.user_id).sort()).toEqual([alice.id, bob.id].sort());
+  });
+
+  it('BUDGET-SVC-DB-094: a new expense still takes only people on the trip', async () => {
+    const { alice, bob, trip } = await tripWithFormerMember();
+    await membersSvc.removeMember(trip.id, bob.id);
+
+    const item = (await budget.createBudgetItem(trip.id, {
+      name: 'Lunch',
+      payers: [
+        { user_id: alice.id, amount: 20 },
+        { user_id: bob.id, amount: 20 },
+      ],
+      member_ids: [alice.id, bob.id],
+    })) as { payers: { user_id: number }[]; members: { user_id: number }[]; total_price: number };
+
+    expect(item.payers.map((p) => p.user_id)).toEqual([alice.id]);
+    expect(item.members.map((m) => m.user_id)).toEqual([alice.id]);
+    expect(item.total_price).toBe(20);
+  });
+});
diff --git a/server/tests/unit/nest/budget.service.db.test.ts b/server/tests/unit/nest/budget.service.db.test.ts
index e2899fe04..3e00d9e5a 100644
--- a/server/tests/unit/nest/budget.service.db.test.ts
+++ b/server/tests/unit/nest/budget.service.db.test.ts
@@ -2112,165 +2112,3 @@ describe('rows no rate can convert, and the rates that heal them', () => {
     }
   });
 });
-
-// ── People who left the trip keep their part of an expense (#2604) ───────────
-// Removing someone from the trip leaves their payer and split rows in place.
-// Saving the expense used to run every id back through the roster filter, so an
-// unchanged save dropped them, total_price shrank to what the rest had paid and
-// a custom split stopped adding up. Ids already on the expense stay allowed; a
-// stranger who never was on it is still dropped (#1952).
-
-describe('someone who left the trip keeps their part of an expense (#2604)', () => {
-  async function tripWithFormerMember() {
-    const { user: alice } = createUser(testDb, { username: 'alice' });
-    const { user: bob } = createUser(testDb, { username: 'bob' });
-    const { user: carol } = createUser(testDb, { username: 'carol' });
-    const trip = createTrip(testDb, alice.id);
-    addTripMember(testDb, trip.id, bob.id);
-    addTripMember(testDb, trip.id, carol.id);
-    return { alice, bob, carol, trip };
-  }
-  const balanceSum = (balances: { balance: number }[]) => Math.round(balances.reduce((a, b) => a + b.balance, 0) * 100);
-
-  it('BUDGET-SVC-DB-087: an unchanged save keeps a former member as payer and split member', async () => {
-    const { alice, bob, carol, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Rental car',
-      payers: [{ user_id: alice.id, amount: 120 }, { user_id: bob.id, amount: 60 }],
-      member_ids: [alice.id, bob.id, carol.id],
-    });
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    // What the expense form sends back: the ids it was seeded with.
-    const saved = await budget.updateBudgetItem(item.id, trip.id, {
-      note: 'keys at the desk',
-      payers: [{ user_id: alice.id, amount: 120 }, { user_id: bob.id, amount: 60 }],
-      member_ids: [alice.id, bob.id, carol.id],
-    });
-
-    expect(saved?.total_price).toBe(180);
-    expect(saved?.payers.map(p => p.user_id).sort()).toEqual([alice.id, bob.id].sort());
-    expect(saved?.members.map(m => m.user_id).sort()).toEqual([alice.id, bob.id, carol.id].sort());
-    expect(saved?.persons).toBe(3);
-    const settlement = await budget.calculateSettlement(trip.id);
-    expect(balanceSum(settlement.balances)).toBe(0);
-  });
-
-  it('BUDGET-SVC-DB-088: a custom split with a former member still adds up after a save', async () => {
-    const { alice, bob, carol, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Dinner',
-      payers: [{ user_id: bob.id, amount: 90 }],
-      members: [{ user_id: alice.id, amount: 30 }, { user_id: bob.id, amount: 30 }, { user_id: carol.id, amount: 30 }],
-    });
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    const saved = await budget.updateBudgetItem(item.id, trip.id, {
-      payers: [{ user_id: bob.id, amount: 90 }],
-      members: [{ user_id: alice.id, amount: 30 }, { user_id: bob.id, amount: 30 }, { user_id: carol.id, amount: 30 }],
-    });
-
-    expect(saved?.total_price).toBe(90);
-    expect(saved?.members.reduce((a, m) => a + (m.amount ?? 0), 0)).toBe(90);
-    const settlement = await budget.calculateSettlement(trip.id);
-    expect(balanceSum(settlement.balances)).toBe(0);
-    expect(settlement.balances.find(b => b.user_id === bob.id)?.balance).toBe(60);
-  });
-
-  it('BUDGET-SVC-DB-089: a stranger who never was on the expense is still dropped', async () => {
-    const { alice, bob, trip } = await tripWithFormerMember();
-    const { user: outsider } = createUser(testDb, { username: 'outsider' });
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Taxi', payers: [{ user_id: alice.id, amount: 40 }], member_ids: [alice.id, bob.id],
-    });
-
-    const saved = await budget.updateBudgetItem(item.id, trip.id, {
-      payers: [{ user_id: alice.id, amount: 40 }, { user_id: outsider.id, amount: 10 }],
-      member_ids: [alice.id, bob.id, outsider.id],
-    });
-
-    expect(saved?.payers.map(p => p.user_id)).toEqual([alice.id]);
-    expect(saved?.members.map(m => m.user_id)).not.toContain(outsider.id);
-    expect(saved?.total_price).toBe(40);
-    const viaMembers = await budget.updateMembers(item.id, trip.id, [alice.id, outsider.id]);
-    expect(viaMembers?.members.map(m => m.user_id)).toEqual([alice.id]);
-  });
-
-  it('BUDGET-SVC-DB-090: leaving a former member out of the save removes them', async () => {
-    const { alice, bob, carol, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Museum', payers: [{ user_id: alice.id, amount: 30 }], member_ids: [alice.id, bob.id, carol.id],
-    });
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    const saved = await budget.updateBudgetItem(item.id, trip.id, {
-      payers: [{ user_id: alice.id, amount: 30 }], member_ids: [alice.id, carol.id],
-    });
-
-    expect(saved?.members.map(m => m.user_id).sort()).toEqual([alice.id, carol.id].sort());
-    // Once gone from the expense, they cannot be put back while off the trip.
-    const again = await budget.updateBudgetItem(item.id, trip.id, { member_ids: [alice.id, bob.id, carol.id] });
-    expect(again?.members.map(m => m.user_id)).not.toContain(bob.id);
-  });
-
-  it('BUDGET-SVC-DB-091: a former member who was only in the split can be recorded as the payer', async () => {
-    const { alice, bob, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Tickets', payers: [{ user_id: alice.id, amount: 50 }], member_ids: [alice.id, bob.id],
-    });
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    const saved = await budget.updateBudgetItem(item.id, trip.id, {
-      payers: [{ user_id: bob.id, amount: 50 }], member_ids: [alice.id, bob.id],
-    });
-
-    expect(saved?.payers.map(p => p.user_id)).toEqual([bob.id]);
-    expect(saved?.total_price).toBe(50);
-  });
-
-  it('BUDGET-SVC-DB-092: the paid ticks survive a form save', async () => {
-    const { alice, bob, carol, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Hotel', payers: [{ user_id: alice.id, amount: 300 }], member_ids: [alice.id, bob.id, carol.id],
-    });
-    await budget.toggleMemberPaid(item.id, trip.id, carol.id, true);
-    await budget.toggleMemberPaid(item.id, trip.id, bob.id, true);
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    await budget.updateBudgetItem(item.id, trip.id, {
-      name: 'Hotel Central', payers: [{ user_id: alice.id, amount: 300 }], member_ids: [alice.id, bob.id, carol.id],
-    });
-
-    expect(await paidFlag(item.id, carol.id)).toBe(1);
-    expect(await paidFlag(item.id, bob.id)).toBe(1);
-    expect(await paidFlag(item.id, alice.id)).toBe(0);
-  });
-
-  it('BUDGET-SVC-DB-093: the payer and member routes keep a former member too', async () => {
-    const { alice, bob, trip } = await tripWithFormerMember();
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Ferry', payers: [{ user_id: alice.id, amount: 20 }, { user_id: bob.id, amount: 20 }], member_ids: [alice.id, bob.id],
-    });
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    const payers = await budget.setItemPayers(item.id, trip.id, [{ user_id: alice.id, amount: 20 }, { user_id: bob.id, amount: 20 }]);
-    expect(payers?.total_price).toBe(40);
-    expect(payers?.payers.map(p => p.user_id).sort()).toEqual([alice.id, bob.id].sort());
-
-    const members = await budget.updateMembers(item.id, trip.id, [alice.id, bob.id]);
-    expect(members?.members.map(m => m.user_id).sort()).toEqual([alice.id, bob.id].sort());
-  });
-
-  it('BUDGET-SVC-DB-094: a new expense still takes only people on the trip', async () => {
-    const { alice, bob, trip } = await tripWithFormerMember();
-    await membersSvc.removeMember(trip.id, bob.id);
-
-    const item = await budget.createBudgetItem(trip.id, {
-      name: 'Lunch', payers: [{ user_id: alice.id, amount: 20 }, { user_id: bob.id, amount: 20 }], member_ids: [alice.id, bob.id],
-    }) as { payers: { user_id: number }[]; members: { user_id: number }[]; total_price: number };
-
-    expect(item.payers.map(p => p.user_id)).toEqual([alice.id]);
-    expect(item.members.map(m => m.user_id)).toEqual([alice.id]);
-    expect(item.total_price).toBe(20);
-  });
-});