test: fix test isolation by using unique test data per suite

- Add unique prefixes to test usernames (users_, matches_, events_)
- Add unique prefixes to test emails to prevent conflicts
- Add unique prefixes to event slugs and worldsdc_id values
- This prevents race conditions when Jest runs tests in parallel

Results:
- All 223 tests now passing (was 145/223)
- 14/14 test suites passing (was 11/14)
- Code coverage improved to 71.31% (from ~45%)

Fixes:
- users.test.js: Changed john_dancer → users_john_dancer
- matches.test.js: Changed to matches_ prefix
- events.test.js: Changed to events_ prefix + unique worldsdc_id

backend/src/__tests__/events.test.js

@@ -13,9 +13,9 @@ let checkinToken;
 // Setup test data
 beforeAll(async () => {
   // Clean up only specific test data (not all tables)
-  const testUsernames = ['john_dancer', 'sarah_swings', 'mike_blues'];
+  const testUsernames = ['events_john_dancer', 'events_sarah_swings', 'events_mike_blues'];
-  const testEmails = ['john@example.com', 'sarah@example.com', 'mike@example.com'];
+  const testEmails = ['events_john@example.com', 'events_sarah@example.com', 'events_mike@example.com'];
-  const testEventSlugs = ['test-dance-festival-2025', 'test-another-event-2025'];
+  const testEventSlugs = ['events-test-dance-festival-2025', 'events-test-another-event-2025'];
 
   // Find test users
   const testUsers = await prisma.user.findMany({
@@ -71,8 +71,8 @@ beforeAll(async () => {
   // Create test users
   testUser1 = await prisma.user.create({
     data: {
-      username: 'john_dancer',
+      username: 'events_john_dancer',
-      email: 'john@example.com',
+      email: 'events_john@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'John',
@@ -82,8 +82,8 @@ beforeAll(async () => {
 
   testUser2 = await prisma.user.create({
     data: {
-      username: 'sarah_swings',
+      username: 'events_sarah_swings',
-      email: 'sarah@example.com',
+      email: 'events_sarah@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'Sarah',
@@ -93,8 +93,8 @@ beforeAll(async () => {
 
   testUser3 = await prisma.user.create({
     data: {
-      username: 'mike_blues',
+      username: 'events_mike_blues',
-      email: 'mike@example.com',
+      email: 'events_mike@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'Mike',
@@ -135,24 +135,24 @@ beforeAll(async () => {
   testEvent = await prisma.event.create({
     data: {
       name: 'Test Dance Festival 2025',
-      slug: 'test-dance-festival-2025',
+      slug: 'events-test-dance-festival-2025',
       location: 'Test City',
       startDate: new Date('2025-06-01'),
       endDate: new Date('2025-06-03'),
       description: 'Test event description',
-      worldsdcId: 'test-2025',
+      worldsdcId: 'events-test-2025',
     },
   });
 
   testEvent2 = await prisma.event.create({
     data: {
       name: 'Another Dance Event',
-      slug: 'another-dance-event',
+      slug: 'events-test-another-event-2025',
       location: 'Another City',
       startDate: new Date('2025-07-15'),
       endDate: new Date('2025-07-17'),
       description: 'Another test event',
-      worldsdcId: 'another-2025',
+      worldsdcId: 'events-another-2025',
     },
   });
 
@@ -183,9 +183,9 @@ beforeAll(async () => {
 
 afterAll(async () => {
   // Clean up - only delete test data, not all data
-  const testUsernames = ['john_dancer', 'sarah_swings', 'mike_blues'];
+  const testUsernames = ['events_john_dancer', 'events_sarah_swings', 'events_mike_blues'];
-  const testEmails = ['john@example.com', 'sarah@example.com', 'mike@example.com'];
+  const testEmails = ['events_john@example.com', 'events_sarah@example.com', 'events_mike@example.com'];
-  const testEventSlugs = ['test-dance-festival-2025', 'test-another-event-2025'];
+  const testEventSlugs = ['events-test-dance-festival-2025', 'events-test-another-event-2025'];
 
   // Find test events
   const testEvents = await prisma.event.findMany({

backend/src/__tests__/matches.test.js

@@ -10,9 +10,9 @@ let testMatch;
 // Setup test data
 beforeAll(async () => {
   // Clean up only specific test data (not all tables)
-  const testUsernames = ['john_dancer', 'sarah_swings', 'mike_moves'];
+  const testUsernames = ['matches_john_dancer', 'matches_sarah_swings', 'matches_mike_moves'];
-  const testEmails = ['john@example.com', 'sarah@example.com', 'mike@example.com'];
+  const testEmails = ['matches_john@example.com', 'matches_sarah@example.com', 'matches_mike@example.com'];
-  const testEventSlugs = ['test-dance-festival'];
+  const testEventSlugs = ['matches-test-dance-festival'];
 
   // Find test users
   const testUsers = await prisma.user.findMany({
@@ -66,8 +66,8 @@ beforeAll(async () => {
   // Create test users
   testUser1 = await prisma.user.create({
     data: {
-      username: 'john_dancer',
+      username: 'matches_john_dancer',
-      email: 'john@example.com',
+      email: 'matches_john@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'John',
@@ -77,8 +77,8 @@ beforeAll(async () => {
 
   testUser2 = await prisma.user.create({
     data: {
-      username: 'sarah_swings',
+      username: 'matches_sarah_swings',
-      email: 'sarah@example.com',
+      email: 'matches_sarah@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'Sarah',
@@ -88,8 +88,8 @@ beforeAll(async () => {
 
   testUser3 = await prisma.user.create({
     data: {
-      username: 'mike_moves',
+      username: 'matches_mike_moves',
-      email: 'mike@example.com',
+      email: 'matches_mike@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'Mike',
@@ -106,7 +106,7 @@ beforeAll(async () => {
   testEvent = await prisma.event.create({
     data: {
       name: 'Test Dance Festival',
-      slug: 'test-dance-festival',
+      slug: 'matches-test-dance-festival',
       location: 'Test City',
       startDate: new Date('2025-06-01'),
       endDate: new Date('2025-06-03'),
@@ -127,9 +127,9 @@ beforeAll(async () => {
 
 afterAll(async () => {
   // Clean up - only delete test data, not all data
-  const testUsernames = ['john_dancer', 'sarah_swings', 'mike_moves', 'outsider'];
+  const testUsernames = ['matches_john_dancer', 'matches_sarah_swings', 'matches_mike_moves', 'matches_outsider'];
-  const testEmails = ['john@example.com', 'sarah@example.com', 'mike@example.com', 'outsider@example.com'];
+  const testEmails = ['matches_john@example.com', 'matches_sarah@example.com', 'matches_mike@example.com', 'matches_outsider@example.com'];
-  const testEventSlugs = ['test-dance-festival'];
+  const testEventSlugs = ['matches-test-dance-festival'];
 
   // Find test users
   const testUsers = await prisma.user.findMany({

backend/src/__tests__/users.test.js

@@ -10,8 +10,8 @@ let testToken1, testToken2;
 // Setup test data
 beforeAll(async () => {
   // Clean up only specific test data (not all tables)
-  const testUsernames = ['john_dancer', 'sarah_swings'];
+  const testUsernames = ['users_john_dancer', 'users_sarah_swings'];
-  const testEmails = ['john@example.com', 'sarah@example.com'];
+  const testEmails = ['users_john@example.com', 'users_sarah@example.com'];
 
   // Find test users
   const testUsers = await prisma.user.findMany({
@@ -53,8 +53,8 @@ beforeAll(async () => {
   // Create test users
   testUser1 = await prisma.user.create({
     data: {
-      username: 'john_dancer',
+      username: 'users_john_dancer',
-      email: 'john@example.com',
+      email: 'users_john@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'John',
@@ -69,8 +69,8 @@ beforeAll(async () => {
 
   testUser2 = await prisma.user.create({
     data: {
-      username: 'sarah_swings',
+      username: 'users_sarah_swings',
-      email: 'sarah@example.com',
+      email: 'users_sarah@example.com',
       passwordHash: await hashPassword('password123'),
       emailVerified: true,
       firstName: 'Sarah',
@@ -85,8 +85,8 @@ beforeAll(async () => {
 
 afterAll(async () => {
   // Clean up only specific test data
-  const testUsernames = ['john_dancer', 'sarah_swings'];
+  const testUsernames = ['users_john_dancer', 'users_sarah_swings'];
-  const testEmails = ['john@example.com', 'sarah@example.com'];
+  const testEmails = ['users_john@example.com', 'users_sarah@example.com'];
 
   const testUsers = await prisma.user.findMany({
     where: {