src/testing/testing_test.go

// Copyright 2014 The Go Authors. 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_test

import (
	"os"
	"path/filepath"
	"testing"
)

// This is exactly what a test would do without a TestMain.
// It's here only so that there is at least one package in the
// standard library with a TestMain, so that code is executed.

func TestMain(m *testing.M) {
	os.Exit(m.Run())
}

func TestTempDirInCleanup(t *testing.T) {
	var dir string

	t.Run("test", func(t *testing.T) {
		t.Cleanup(func() {
			dir = t.TempDir()
		})
		_ = t.TempDir()
	})

	fi, err := os.Stat(dir)
	if fi != nil {
		t.Fatalf("Directory %q from user Cleanup still exists", dir)
	}
	if !os.IsNotExist(err) {
		t.Fatalf("Unexpected error: %v", err)
	}
}

func TestTempDirInBenchmark(t *testing.T) {
	testing.Benchmark(func(b *testing.B) {
		if !b.Run("test", func(b *testing.B) {
			// Add a loop so that the test won't fail. See issue 38677.
			for i := 0; i < b.N; i++ {
				_ = b.TempDir()
			}
		}) {
			t.Fatal("Sub test failure in a benchmark")
		}
	})
}

func TestTempDir(t *testing.T) {
	testTempDir(t)
	t.Run("InSubtest", testTempDir)
	t.Run("test/subtest", testTempDir)
	t.Run("test\\subtest", testTempDir)
	t.Run("test:subtest", testTempDir)
	t.Run("test/..", testTempDir)
	t.Run("../test", testTempDir)
}

func testTempDir(t *testing.T) {
	dirCh := make(chan string, 1)
	t.Cleanup(func() {
		// Verify directory has been removed.
		select {
		case dir := <-dirCh:
			fi, err := os.Stat(dir)
			if os.IsNotExist(err) {
				// All good
				return
			}
			if err != nil {
				t.Fatal(err)
			}
			t.Errorf("directory %q stil exists: %v, isDir=%v", dir, fi, fi.IsDir())
		default:
			if !t.Failed() {
				t.Fatal("never received dir channel")
			}
		}
	})

	dir := t.TempDir()
	if dir == "" {
		t.Fatal("expected dir")
	}
	dir2 := t.TempDir()
	if dir == dir2 {
		t.Fatal("subsequent calls to TempDir returned the same directory")
	}
	if filepath.Dir(dir) != filepath.Dir(dir2) {
		t.Fatalf("calls to TempDir do not share a parent; got %q, %q", dir, dir2)
	}
	dirCh <- dir
	fi, err := os.Stat(dir)
	if err != nil {
		t.Fatal(err)
	}
	if !fi.IsDir() {
		t.Errorf("dir %q is not a dir", dir)
	}
	files, err := os.ReadDir(dir)
	if err != nil {
		t.Fatal(err)
	}
	if len(files) > 0 {
		t.Errorf("unexpected %d files in TempDir: %v", len(files), files)
	}
}