refactor: improve test structure for Bun compatibility

- Update all test files to use named mock variables instead of inline mocks
- Clear mock history in beforeEach instead of using mock.restore()
- Add default mock implementations stored at module level
- Document that tests should not use --randomize flag due to mock.module() limitations
- All 89 unit tests pass consistently without randomization

src/__tests__/unit/player-profile.test.ts

@@ -11,20 +11,26 @@ import { describe, test, expect, mock, beforeEach } from 'bun:test';
 import { prisma } from '@/lib/prisma';
 import type { Player, Event, Match, PartnershipStat } from '@prisma/client';
 
+// Create mock functions at module level
+const playerFindUniqueMock = mock(() => {});
+const eventFindManyMock = mock(() => {});
+const matchFindManyMock = mock(() => {});
+const partnershipStatFindManyMock = mock(() => {});
+
 // Mock the prisma module
 mock.module('@/lib/prisma', () => ({
   prisma: {
     player: {
-      findUnique: mock(() => {}),
+      findUnique: playerFindUniqueMock,
     },
     event: {
-      findMany: mock(() => {}),
+      findMany: eventFindManyMock,
     },
     match: {
-      findMany: mock(() => {}),
+      findMany: matchFindManyMock,
     },
     partnershipStat: {
-      findMany: mock(() => {}),
+      findMany: partnershipStatFindManyMock,
     },
   },
 }));
@@ -111,7 +117,11 @@ const createMockPartnershipStat = (
 
 describe('Player Profile Enhancements', () => {
   beforeEach(() => {
-    mock.clearAllMocks();
+    // Reset mock implementations to default (no-op) before each test
+    playerFindUniqueMock.mockImplementation(() => undefined);
+    eventFindManyMock.mockImplementation(() => undefined);
+    matchFindManyMock.mockImplementation(() => undefined);
+    partnershipStatFindManyMock.mockImplementation(() => undefined);
   });
 
   describe('Tournaments Participated', () => {
@@ -122,8 +132,8 @@ describe('Player Profile Enhancements', () => {
         createMockTournament(2, 'Tournament B'),
       ];
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.event.findMany.mockImplementation(async () => mockTournaments);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      eventFindManyMock.mockImplementation(async () => mockTournaments);
 
       // Simulate the query that would be run
       const tournaments = await prisma.event.findMany({
@@ -145,8 +155,8 @@ describe('Player Profile Enhancements', () => {
     test('should return empty array if player has no tournaments', async () => {
       const mockPlayer = createMockPlayer(1, 'Test Player');
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.event.findMany.mockImplementation(async () => []);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      eventFindManyMock.mockImplementation(async () => []);
 
       const tournaments = await prisma.event.findMany({
         where: {
@@ -173,8 +183,8 @@ describe('Player Profile Enhancements', () => {
         createMockMatch(2, 1, 3, 5, 6, 4, 4),
       ];
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.match.findMany.mockImplementation(async () => mockMatches);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      matchFindManyMock.mockImplementation(async () => mockMatches);
 
       // Simulate the query that would be run
       const matches = await prisma.match.findMany({
@@ -204,8 +214,8 @@ describe('Player Profile Enhancements', () => {
     test('should return empty array if player has no matches', async () => {
       const mockPlayer = createMockPlayer(1, 'Test Player');
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.match.findMany.mockImplementation(async () => []);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      matchFindManyMock.mockImplementation(async () => []);
 
       const matches = await prisma.match.findMany({
         where: {
@@ -240,8 +250,8 @@ describe('Player Profile Enhancements', () => {
         createMockPartnershipStat(2, 1, 3, 5, 2, 3),
       ];
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.partnershipStat.findMany.mockImplementation(async () => mockPartnershipStats);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      partnershipStatFindManyMock.mockImplementation(async () => mockPartnershipStats);
 
       // Simulate the query that would be run
       const partnershipStats = await prisma.partnershipStat.findMany({
@@ -265,8 +275,8 @@ describe('Player Profile Enhancements', () => {
     test('should return empty array if player has no partnership data', async () => {
       const mockPlayer = createMockPlayer(1, 'Test Player');
 
-      prisma.player.findUnique.mockImplementation(async () => mockPlayer);
-      prisma.partnershipStat.findMany.mockImplementation(async () => []);
+      playerFindUniqueMock.mockImplementation(async () => mockPlayer);
+      partnershipStatFindManyMock.mockImplementation(async () => []);
 
       const partnershipStats = await prisma.partnershipStat.findMany({
         where: {