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-deduplication.test.ts

@@ -4,15 +4,19 @@
  * Tests the player deduplication logic for CSV uploads
  */
 
-import { describe, test, expect, mock, beforeEach } from 'bun:test';
+import { describe, test, expect, mock, beforeEach,} from 'bun:test';
 import { prisma } from '@/lib/prisma';
 
+// Create mock functions at module level
+const playerFindFirstMock = mock(() => {});
+const playerCreateMock = mock(() => {});
+
 // Mock the prisma module
 mock.module('@/lib/prisma', () => ({
   prisma: {
     player: {
-      findFirst: mock(() => {}),
-      create: mock(() => {}),
+      findFirst: playerFindFirstMock,
+      create: playerCreateMock,
     },
   },
 }));
@@ -46,7 +50,9 @@ async function findOrCreatePlayer(name: string) {
 
 describe('Player Deduplication', () => {
   beforeEach(() => {
-    mock.clearAllMocks();
+    // Clear all mock history before each test
+    playerFindFirstMock.mockClear();
+    playerCreateMock.mockClear();
   });
 
   describe('findOrCreatePlayer', () => {
@@ -64,7 +70,7 @@ describe('Player Deduplication', () => {
         rating: 0,
       };
 
-      prisma.player.findFirst.mockImplementation(async () => mockPlayer);
+      playerFindFirstMock.mockImplementation(async () => mockPlayer);
 
       const result = await findOrCreatePlayer('Emily');
 
@@ -89,7 +95,7 @@ describe('Player Deduplication', () => {
         rating: 0,
       };
 
-      prisma.player.findFirst.mockImplementation(async () => mockPlayer);
+      playerFindFirstMock.mockImplementation(async () => mockPlayer);
 
       const result = await findOrCreatePlayer('EMILY');
 
@@ -114,7 +120,7 @@ describe('Player Deduplication', () => {
         rating: 0,
       };
 
-      prisma.player.findFirst.mockImplementation(async () => mockPlayer);
+      playerFindFirstMock.mockImplementation(async () => mockPlayer);
 
       const result = await findOrCreatePlayer('  Emily  ');
 
@@ -126,7 +132,7 @@ describe('Player Deduplication', () => {
     });
 
     test('should create new player if not found', async () => {
-      prisma.player.findFirst.mockImplementation(async () => null);
+      playerFindFirstMock.mockImplementation(async () => null);
 
       const newPlayer = {
         id: 100,
@@ -141,7 +147,7 @@ describe('Player Deduplication', () => {
         updatedAt: new Date(),
       };
 
-      prisma.player.create.mockImplementation(async () => newPlayer);
+      playerCreateMock.mockImplementation(async () => newPlayer);
 
       const result = await findOrCreatePlayer('NewPlayer');
 
@@ -162,7 +168,7 @@ describe('Player Deduplication', () => {
     });
 
     test('should handle names with special characters', async () => {
-      prisma.player.findFirst.mockImplementation(async () => null);
+      playerFindFirstMock.mockImplementation(async () => null);
 
       const newPlayer = {
         id: 100,
@@ -177,7 +183,7 @@ describe('Player Deduplication', () => {
         updatedAt: new Date(),
       };
 
-      prisma.player.create.mockImplementation(async () => newPlayer);
+      playerCreateMock.mockImplementation(async () => newPlayer);
 
       const result = await findOrCreatePlayer('Test-Player_123');
 
@@ -195,7 +201,7 @@ describe('Player Deduplication', () => {
     });
 
     test('should handle names with spaces', async () => {
-      prisma.player.findFirst.mockImplementation(async () => null);
+      playerFindFirstMock.mockImplementation(async () => null);
 
       const newPlayer = {
         id: 100,
@@ -210,7 +216,7 @@ describe('Player Deduplication', () => {
         updatedAt: new Date(),
       };
 
-      prisma.player.create.mockImplementation(async () => newPlayer);
+      playerCreateMock.mockImplementation(async () => newPlayer);
 
       const result = await findOrCreatePlayer('Dave B');
 
@@ -242,7 +248,7 @@ describe('Player Deduplication', () => {
         rating: 0,
       };
 
-      prisma.player.findFirst.mockImplementation(async () => mockPlayer);
+      playerFindFirstMock.mockImplementation(async () => mockPlayer);
 
       const result1 = await findOrCreatePlayer('EMILY');
       const result2 = await findOrCreatePlayer('Emily');
@@ -255,7 +261,7 @@ describe('Player Deduplication', () => {
     });
 
     test('should handle empty or whitespace-only names', async () => {
-      prisma.player.findFirst.mockImplementation(async () => null);
+      playerFindFirstMock.mockImplementation(async () => null);
 
       const newPlayer = {
         id: 100,
@@ -270,7 +276,7 @@ describe('Player Deduplication', () => {
         updatedAt: new Date(),
       };
 
-      prisma.player.create.mockImplementation(async () => newPlayer);
+      playerCreateMock.mockImplementation(async () => newPlayer);
 
       const result = await findOrCreatePlayer('   ');
 
@@ -320,7 +326,7 @@ describe('Player Deduplication', () => {
         rating: 0,
       };
 
-      prisma.player.findFirst
+      playerFindFirstMock
         .mockResolvedValueOnce(existingPlayer) // First call for "Emily"
         .mockResolvedValueOnce(existingPlayer) // Second call for "EMILY"
         .mockResolvedValueOnce(existingPlayer); // Third call for "  Emily  "