diff --git a/cmd/server/tests/test_helpers.go b/cmd/server/tests/test_helpers.go
index b24b425..4f41ff3 100644
--- a/cmd/server/tests/test_helpers.go
+++ b/cmd/server/tests/test_helpers.go
@@ -212,13 +212,13 @@ func setupDeviceTest(t *testing.T) *TestDeviceSetup {
 // createTestUserOnce returns the pre-created test user info
 func createTestUserOnce(t *testing.T, db *database.Queries) UserTestData {
 	ctx := context.Background()
-	user, err := db.GetUserByEmail(ctx, "testuser@example.com")
+	user, err := db.GetUserByEmail(ctx, "testuser@tests.bookhoard.internal")
 	require.NoError(t, err, "Test user should exist (created by setupTestServer)")
 	userUUID, err := uuid.FromBytes(user.ID.Bytes[0:16])
 	require.NoError(t, err, "Should parse user UUID")
 	return UserTestData{
 		ID:       userUUID,
-		Email:    "testuser@example.com",
+		Email:    "testuser@tests.bookhoard.internal",
 		Username: "testuser",
 		Password: "Test@Pass123!",
 	}
@@ -228,7 +228,7 @@ func createTestUserOnce(t *testing.T, db *database.Queries) UserTestData {
 func createRegularUserOnce(t *testing.T, db *database.Queries) UserTestData {
 	ctx := context.Background()
 	uniqueID := uuid.New().String()[:8]
-	email := fmt.Sprintf("regularuser-%s@example.com", uniqueID)
+	email := fmt.Sprintf("regularuser-%s@tests.bookhoard.internal", uniqueID)
 	username := fmt.Sprintf("regularuser-%s", uniqueID)
 
 	passwordHash := "$2a$10$JjAtK7PPa1WexQC3AUGe8OXLeuseZ/haN1Mz7emMo6CfOvMiTVXWq"
@@ -518,18 +518,21 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 
 	ctx := context.Background()
 
-	// Delete existing test users if they exist (cascades to delete collections, media items, etc.)
-	for _, email := range []string{"testuser@example.com", "testregularuser@example.com"} {
-		existingUser, err := queries.GetUserByEmail(ctx, email)
-		if err == nil {
-			queries.DeleteUser(ctx, existingUser.ID)
+	// Delete ALL test users (any user with test email domains) to ensure clean state
+	// This handles users created during tests that may have been promoted to admin, etc.
+	allUsers, err := queries.ListUsers(ctx)
+	if err == nil {
+		for _, user := range allUsers {
+			if strings.HasSuffix(user.Email, "@example.com") || strings.HasSuffix(user.Email, "@tests.bookhoard.internal") {
+				queries.DeleteUser(ctx, user.ID)
+			}
 		}
 	}
 
 	// Create fresh admin test user
 	passwordHash := "$2a$10$JjAtK7PPa1WexQC3AUGe8OXLeuseZ/haN1Mz7emMo6CfOvMiTVXWq"
 	adminUser, err := queries.CreateUser(ctx, database.CreateUserParams{
-		Email:        "testuser@example.com",
+		Email:        "testuser@tests.bookhoard.internal",
 		Username:     "testuser",
 		PasswordHash: passwordHash,
 		FirstName:    pgtype.Text{String: "Test", Valid: true},
@@ -544,7 +547,7 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 
 	// Create fresh regular test user
 	regularUser, err := queries.CreateUser(ctx, database.CreateUserParams{
-		Email:        "testregularuser@example.com",
+		Email:        "testregularuser@tests.bookhoard.internal",
 		Username:     "testregularuser",
 		PasswordHash: passwordHash,
 		FirstName:    pgtype.Text{String: "Regular", Valid: true},
@@ -558,8 +561,8 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 	createDefaultCollectionsForUser(t, queries, pgtype.UUID{Bytes: regularUUID, Valid: true})
 
 	// Login to get tokens
-	adminToken := loginWithCredentials(t, ts, "testuser@example.com", "Test@Pass123!")
-	regularToken := loginWithCredentials(t, ts, "testregularuser@example.com", "Test@Pass123!")
+	adminToken := loginWithCredentials(t, ts, "testuser@tests.bookhoard.internal", "Test@Pass123!")
+	regularToken := loginWithCredentials(t, ts, "testregularuser@tests.bookhoard.internal", "Test@Pass123!")
 
 	// Create TestServerSetup struct with all resources
 	setup := &TestServerSetup{
@@ -615,7 +618,7 @@ func loginWithCredentials(t *testing.T, ts *httptest.Server, email, password str
 
 func getTestUserID(t *testing.T, db *database.Queries) uuid.UUID {
 	ctx := context.Background()
-	user, err := db.GetUserByEmail(ctx, "testuser@example.com")
+	user, err := db.GetUserByEmail(ctx, "testuser@tests.bookhoard.internal")
 	require.NoError(t, err, "Test user should exist")
 	userUUID, err := uuid.FromBytes(user.ID.Bytes[:])
 	require.NoError(t, err, "Failed to parse user UUID")
@@ -624,7 +627,7 @@ func getTestUserID(t *testing.T, db *database.Queries) uuid.UUID {
 
 func getRegularUserID(t *testing.T, db *database.Queries) uuid.UUID {
 	ctx := context.Background()
-	user, err := db.GetUserByEmail(ctx, "testregularuser@example.com")
+	user, err := db.GetUserByEmail(ctx, "testregularuser@tests.bookhoard.internal")
 	require.NoError(t, err, "Regular user should exist")
 	userUUID, err := uuid.FromBytes(user.ID.Bytes[:])
 	require.NoError(t, err, "Failed to parse user UUID")