src/os/read_test.go

// Copyright 2009 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 os_test

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

func checkNamedSize(t *testing.T, path string, size int64) {
	dir, err := Stat(path)
	if err != nil {
		t.Fatalf("Stat %q (looking for size %d): %s", path, size, err)
	}
	if dir.Size() != size {
		t.Errorf("Stat %q: size %d want %d", path, dir.Size(), size)
	}
}

func TestReadFile(t *testing.T) {
	filename := "rumpelstilzchen"
	contents, err := ReadFile(filename)
	if err == nil {
		t.Fatalf("ReadFile %s: error expected, none found", filename)
	}

	filename = "read_test.go"
	contents, err = ReadFile(filename)
	if err != nil {
		t.Fatalf("ReadFile %s: %v", filename, err)
	}

	checkNamedSize(t, filename, int64(len(contents)))
}

func TestWriteFile(t *testing.T) {
	f, err := CreateTemp("", "ioutil-test")
	if err != nil {
		t.Fatal(err)
	}
	defer f.Close()
	defer Remove(f.Name())

	msg := "Programming today is a race between software engineers striving to " +
		"build bigger and better idiot-proof programs, and the Universe trying " +
		"to produce bigger and better idiots. So far, the Universe is winning."

	if err := WriteFile(f.Name(), []byte(msg), 0644); err != nil {
		t.Fatalf("WriteFile %s: %v", f.Name(), err)
	}

	data, err := ReadFile(f.Name())
	if err != nil {
		t.Fatalf("ReadFile %s: %v", f.Name(), err)
	}

	if string(data) != msg {
		t.Fatalf("ReadFile: wrong data:\nhave %q\nwant %q", string(data), msg)
	}
}

func TestReadOnlyWriteFile(t *testing.T) {
	if Getuid() == 0 {
		t.Skipf("Root can write to read-only files anyway, so skip the read-only test.")
	}

	// We don't want to use CreateTemp directly, since that opens a file for us as 0600.
	tempDir, err := MkdirTemp("", t.Name())
	if err != nil {
		t.Fatal(err)
	}
	defer RemoveAll(tempDir)
	filename := filepath.Join(tempDir, "blurp.txt")

	shmorp := []byte("shmorp")
	florp := []byte("florp")
	err = WriteFile(filename, shmorp, 0444)
	if err != nil {
		t.Fatalf("WriteFile %s: %v", filename, err)
	}
	err = WriteFile(filename, florp, 0444)
	if err == nil {
		t.Fatalf("Expected an error when writing to read-only file %s", filename)
	}
	got, err := ReadFile(filename)
	if err != nil {
		t.Fatalf("ReadFile %s: %v", filename, err)
	}
	if !bytes.Equal(got, shmorp) {
		t.Fatalf("want %s, got %s", shmorp, got)
	}
}

func TestReadDir(t *testing.T) {
	dirname := "rumpelstilzchen"
	_, err := ReadDir(dirname)
	if err == nil {
		t.Fatalf("ReadDir %s: error expected, none found", dirname)
	}

	dirname = "."
	list, err := ReadDir(dirname)
	if err != nil {
		t.Fatalf("ReadDir %s: %v", dirname, err)
	}

	foundFile := false
	foundSubDir := false
	for _, dir := range list {
		switch {
		case !dir.IsDir() && dir.Name() == "read_test.go":
			foundFile = true
		case dir.IsDir() && dir.Name() == "exec":
			foundSubDir = true
		}
	}
	if !foundFile {
		t.Fatalf("ReadDir %s: read_test.go file not found", dirname)
	}
	if !foundSubDir {
		t.Fatalf("ReadDir %s: exec directory not found", dirname)
	}
}