feat: use database transactions to ensure atomicity

cmd/goyco/commands/seed.go

@@ -57,10 +57,15 @@ func HandleSeedCommand(cfg *config.Config, name string, args []string) error {
 	}
 
 	return withDatabase(cfg, func(db *gorm.DB) error {
-		userRepo := repositories.NewUserRepository(db)
+		return db.Transaction(func(tx *gorm.DB) error {
-		postRepo := repositories.NewPostRepository(db)
+			userRepo := repositories.NewUserRepository(db).WithTx(tx)
-		voteRepo := repositories.NewVoteRepository(db)
+			postRepo := repositories.NewPostRepository(db).WithTx(tx)
-		return runSeedCommand(userRepo, postRepo, voteRepo, fs.Args())
+			voteRepo := repositories.NewVoteRepository(db).WithTx(tx)
+			if err := runSeedCommand(userRepo, postRepo, voteRepo, fs.Args()); err != nil {
+				return err
+			}
+			return nil
+		})
 	})
 }
 

cmd/goyco/commands/seed_test.go

@@ -362,3 +362,86 @@ func findSeedUser(users []database.User) *database.User {
 	}
 	return nil
 }
+
+func TestSeedCommandTransactionRollback(t *testing.T) {
+	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("Failed to connect to database: %v", err)
+	}
+
+	err = db.AutoMigrate(&database.User{}, &database.Post{}, &database.Vote{})
+	if err != nil {
+		t.Fatalf("Failed to migrate database: %v", err)
+	}
+
+	userRepo := repositories.NewUserRepository(db)
+	postRepo := repositories.NewPostRepository(db)
+	voteRepo := repositories.NewVoteRepository(db)
+
+	t.Run("transaction rolls back on failure", func(t *testing.T) {
+		initialUserCount, _ := userRepo.Count()
+		initialPostCount, _ := postRepo.Count()
+		initialVoteCount, _ := voteRepo.Count()
+
+		err := db.Transaction(func(tx *gorm.DB) error {
+			txUserRepo := userRepo.WithTx(tx)
+			txPostRepo := postRepo.WithTx(tx)
+			txVoteRepo := voteRepo.WithTx(tx)
+
+			err := seedDatabase(txUserRepo, txPostRepo, txVoteRepo, []string{"--users", "2", "--posts", "3"})
+			if err != nil {
+				return err
+			}
+
+			return fmt.Errorf("simulated failure")
+		})
+
+		if err == nil {
+			t.Fatal("Expected transaction to fail")
+		}
+
+		finalUserCount, _ := userRepo.Count()
+		finalPostCount, _ := postRepo.Count()
+		finalVoteCount, _ := voteRepo.Count()
+
+		if finalUserCount != initialUserCount {
+			t.Errorf("Expected user count to remain %d after rollback, got %d", initialUserCount, finalUserCount)
+		}
+		if finalPostCount != initialPostCount {
+			t.Errorf("Expected post count to remain %d after rollback, got %d", initialPostCount, finalPostCount)
+		}
+		if finalVoteCount != initialVoteCount {
+			t.Errorf("Expected vote count to remain %d after rollback, got %d", initialVoteCount, finalVoteCount)
+		}
+	})
+
+	t.Run("transaction commits on success", func(t *testing.T) {
+		initialUserCount, _ := userRepo.Count()
+		initialPostCount, _ := postRepo.Count()
+
+		err := db.Transaction(func(tx *gorm.DB) error {
+			txUserRepo := userRepo.WithTx(tx)
+			txPostRepo := postRepo.WithTx(tx)
+			txVoteRepo := voteRepo.WithTx(tx)
+
+			return seedDatabase(txUserRepo, txPostRepo, txVoteRepo, []string{"--users", "1", "--posts", "1"})
+		})
+
+		if err != nil {
+			t.Fatalf("Expected transaction to succeed, got error: %v", err)
+		}
+
+		finalUserCount, _ := userRepo.Count()
+		finalPostCount, _ := postRepo.Count()
+
+		expectedUsers := initialUserCount + 2
+		expectedPosts := initialPostCount + 1
+
+		if finalUserCount < expectedUsers {
+			t.Errorf("Expected at least %d users after commit, got %d", expectedUsers, finalUserCount)
+		}
+		if finalPostCount < expectedPosts {
+			t.Errorf("Expected at least %d posts after commit, got %d", expectedPosts, finalPostCount)
+		}
+	})
+}