Add example of tests with transactional cleanup

Author: xorcare

README.md

@@ -78,6 +78,8 @@ total:	(statements)	100.0%
   package.
 - Example of integration testing with isolated database for each testcase
 [](https://github.com/xorcare/testing-go-code-with-postgres/blob/main/user_repository_with_isolated_database_test.go).
+- Example of integration testing with transaction cleanup for each testcase
+[](https://github.com/xorcare/testing-go-code-with-postgres/blob/main/user_repository_with_transactional_cleanup_test.go).
 - And example
   of [GitHub Actions](https://github.com/xorcare/testing-go-code-with-postgres/blob/main/.github/workflows/go.yml)
   and [Gitlab CI](https://github.com/xorcare/testing-go-code-with-postgres/blob/main/.gitlab-ci.yml).

docker-compose.yml

@@ -8,7 +8,7 @@ services:
       POSTGRES_DB: postgres
       POSTGRES_PASSWORD: postgres
       POSTGRES_USER: postgres
-      POSTGRES_MULTIPLE_DATABASES: reference
+      POSTGRES_MULTIPLE_DATABASES: reference, transaction
     healthcheck:
       test: pg_isready --username "postgres" --dbname "reference"
       interval: 1s
@@ -21,7 +21,7 @@ services:
     tmpfs:
       - /var/lib/postgresql/data:rw # Necessary to speed up integration tests.
 
-  migrate:
+  migrate-reference:
     image: migrate/migrate:v4.16.2
     command: >
       -source 'file:///migrations'
@@ -31,3 +31,25 @@ services:
         condition: service_healthy
     volumes:
       - ./migrations:/migrations:ro
+
+  migrate-transaction:
+    image: migrate/migrate:v4.16.2
+    command: >
+      -source 'file:///migrations'
+      -database 'postgresql://postgres:postgres@postgres:5432/transaction?sslmode=disable' up
+    depends_on:
+      postgres:
+        condition: service_healthy
+    volumes:
+      - ./migrations:/migrations:ro
+
+  migrate:
+    image: postgres:15.3-alpine3.18
+    command: echo 'All migrations have been successfully applied!'
+    depends_on:
+      postgres:
+        condition: service_healthy
+      migrate-reference:
+        condition: service_completed_successfully
+      migrate-transaction:
+        condition: service_completed_successfully

testingpg/testingpg.go

@@ -31,8 +31,36 @@ type TestingT interface {
 	Failed() bool
 }
 
+const defaultPostgresURL = "postgresql://postgres:postgres@localhost:32260/postgres?sslmode=disable"
+
 func NewWithIsolatedDatabase(t TestingT) *Postgres {
-	return newPostgres(t).cloneFromReference()
+	return newPostgres(t, defaultPostgresURL).cloneFromReference()
+}
+
+func NewWithTransactionalCleanup(t TestingT) interface {
+	ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error)
+	QueryRowContext(ctx context.Context, query string, args ...any) *sql.Row
+} {
+	// databaseName a separate database is used for transactional cleanup.
+	const databaseName = "transaction"
+
+	postgres := newPostgres(t, defaultPostgresURL)
+	postgres = postgres.replaceDBName(databaseName)
+
+	ctx, done := context.WithCancel(context.Background())
+	t.Cleanup(done)
+
+	tx, err := postgres.DB().BeginTx(ctx, &sql.TxOptions{
+		Isolation: sql.LevelRepeatableRead,
+		ReadOnly:  false,
+	})
+	require.NoError(t, err)
+
+	t.Cleanup(func() {
+		require.NoError(t, tx.Rollback())
+	})
+
+	return tx
 }
 
 type Postgres struct {
@@ -45,10 +73,10 @@ type Postgres struct {
 	sqlDBOnce sync.Once
 }
 
-func newPostgres(t TestingT) *Postgres {
+func newPostgres(t TestingT, defaultPostgresURL string) *Postgres {
 	urlStr := os.Getenv("TESTING_DB_URL")
 	if urlStr == "" {
-		urlStr = "postgresql://postgres:postgres@localhost:32260/postgres?sslmode=disable"
+		urlStr = defaultPostgresURL
 
 		const format = "env TESTING_DB_URL is empty, used default value: %s"
 
@@ -105,11 +133,22 @@ func (p *Postgres) cloneFromReference() *Postgres {
 		require.NoError(p.t, err)
 	})
 
+	return p.replaceDBName(newDBName)
+}
+
+func (p *Postgres) replaceDBName(newDBName string) *Postgres {
+	o := p.clone()
+	o.url = replaceDBName(p.t, p.URL(), newDBName)
+
+	return o
+}
+
+func (p *Postgres) clone() *Postgres {
 	return &Postgres{
 		t: p.t,
 
-		url: replaceDBName(p.t, p.URL(), newDBName),
-		ref: newDBName,
+		url: p.url,
+		ref: p.ref,
 	}
 }
 
@@ -176,7 +215,7 @@ func open(t TestingT, dataSourceURL string) *sql.DB {
 
 	// Automatically close connection after the test is completed.
 	t.Cleanup(func() {
-		db.Close()
+		require.NoError(t, db.Close())
 	})
 
 	return db

testingpg/testingpg_test.go

@@ -69,9 +69,9 @@ func TestNewPostgres(t *testing.T) {
 		ctx := context.Background()
 
 		// Act
-		const sql = `CREATE TABLE "no_conflict" (id integer PRIMARY KEY)`
-		_, err1 := postgres1.DB().ExecContext(ctx, sql)
-		_, err2 := postgres2.DB().ExecContext(ctx, sql)
+		const sqlStr = `CREATE TABLE "no_conflict" (id integer PRIMARY KEY)`
+		_, err1 := postgres1.DB().ExecContext(ctx, sqlStr)
+		_, err2 := postgres2.DB().ExecContext(ctx, sqlStr)
 
 		// Assert
 		require.NoError(t, err1)
@@ -93,3 +93,54 @@ func TestNewPostgres(t *testing.T) {
 		require.NotEqual(t, url1, url2)
 	})
 }
+
+func TestNewWithTransactionalCleanup(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
+	t.Parallel()
+
+	t.Run("Successfully obtained a version", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		tx := testingpg.NewWithTransactionalCleanup(t)
+		ctx := context.Background()
+
+		// Act
+		var version string
+		err := tx.QueryRowContext(ctx, "SELECT version();").Scan(&version)
+
+		// Assert
+		require.NoError(t, err)
+		require.NotEmpty(t, version)
+
+		t.Log(version)
+	})
+
+	t.Run("Changes are not visible in different instances", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		ctx := context.Background()
+		const sqlStr = `CREATE TABLE "no_conflict" (id integer PRIMARY KEY)`
+
+		t.Run("Arrange", func(t *testing.T) {
+			tx := testingpg.NewWithTransactionalCleanup(t)
+			_, err := tx.ExecContext(ctx, sqlStr)
+			require.NoError(t, err)
+		})
+
+		var err error
+
+		// Act
+		t.Run("Act", func(t *testing.T) {
+			tx := testingpg.NewWithTransactionalCleanup(t)
+			_, err = tx.ExecContext(ctx, sqlStr)
+		})
+
+		// Assert
+		require.NoError(t, err, "side effects must be isolated for each instance")
+	})
+}

user_repository_test.go

@@ -4,3 +4,4 @@ package testing_go_code_with_postgres_test
 // database cleanup, this file is empty. The specific tests can be found
 // in the following files:
 // - user_repository_with_isolated_database_test.go
+// - user_repository_with_transactional_cleanup_test.go

user_repository_with_transactional_cleanup_test.go

@@ -0,0 +1,96 @@
+// Copyright (c) 2023 Vasiliy Vasilyuk. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testing_go_code_with_postgres_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+
+	rootpkg "github.com/xorcare/testing-go-code-with-postgres"
+	"github.com/xorcare/testing-go-code-with-postgres/testingpg"
+)
+
+func Test_Transactional_UserRepository_CreateUser(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
+	t.Parallel()
+
+	newFullyFiledUser := func() rootpkg.User {
+		return rootpkg.User{
+			ID:        uuid.New(),
+			Username:  "gopher",
+			CreatedAt: time.Now().Truncate(time.Microsecond),
+		}
+	}
+
+	t.Run("Successfully created a User", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		db := testingpg.NewWithTransactionalCleanup(t)
+		repo := rootpkg.NewUserRepository(db)
+
+		user := newFullyFiledUser()
+
+		// Act
+		err := repo.CreateUser(context.Background(), user)
+
+		// Assert
+		require.NoError(t, err)
+
+		gotUser, err := repo.ReadUser(context.Background(), user.ID)
+		require.NoError(t, err)
+
+		require.Equal(t, user, gotUser)
+	})
+
+	t.Run("Cannot create a user with the same ID", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		db := testingpg.NewWithTransactionalCleanup(t)
+		repo := rootpkg.NewUserRepository(db)
+
+		user := newFullyFiledUser()
+
+		err := repo.CreateUser(context.Background(), user)
+		require.NoError(t, err)
+
+		// Act
+		err = repo.CreateUser(context.Background(), user)
+
+		// Assert
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "duplicate key value violates unique constraint")
+	})
+}
+
+func Test_Transactional_UserRepository_ReadUser(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
+	t.Parallel()
+
+	t.Run("Get an error if the user does not exist", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		db := testingpg.NewWithTransactionalCleanup(t)
+		repo := rootpkg.NewUserRepository(db)
+
+		// Act
+		_, err := repo.ReadUser(context.Background(), uuid.New())
+
+		// Assert
+		require.Error(t, err)
+	})
+}