Publish an example testing go code with Postgres

testingpg/testingpg_test.go

@@ -0,0 +1,95 @@
+// 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 testingpg_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/stretchr/testify/require"
+
+	"github.com/xorcare/testing-go-code-with-postgres/testingpg"
+)
+
+func TestNewPostgres(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
+	t.Parallel()
+
+	t.Run("Successfully connect by URL and get version", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		postgres := testingpg.New(t)
+
+		ctx := context.Background()
+		dbPool, err := pgxpool.New(ctx, postgres.URL())
+		require.NoError(t, err)
+
+		// Act
+		var version string
+		err = dbPool.QueryRow(ctx, "SELECT version();").Scan(&version)
+
+		// Assert
+		require.NoError(t, err)
+		require.NotEmpty(t, version)
+		t.Log(version)
+	})
+
+	t.Run("Successfully obtained a version using a pre-configured conn", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		postgres := testingpg.New(t)
+		ctx := context.Background()
+
+		// Act
+		var version string
+		err := postgres.PgxPool().QueryRow(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
+		postgres1 := testingpg.New(t)
+		postgres2 := testingpg.New(t)
+
+		ctx := context.Background()
+
+		// Act
+		const sql = `CREATE TABLE "no_conflict" (id integer PRIMARY KEY)`
+		_, err1 := postgres1.PgxPool().Exec(ctx, sql)
+		_, err2 := postgres2.PgxPool().Exec(ctx, sql)
+
+		// Assert
+		require.NoError(t, err1)
+		require.NoError(t, err2, "databases must be isolated for each instance")
+	})
+
+	t.Run("URL is different at different instances", func(t *testing.T) {
+		t.Parallel()
+
+		// Arrange
+		postgres1 := testingpg.New(t)
+		postgres2 := testingpg.New(t)
+
+		// Act
+		url1 := postgres1.URL()
+		url2 := postgres2.URL()
+
+		// Assert
+		require.NotEqual(t, url1, url2)
+	})
+}