github.com/code-reading/golang@v0.0.0-20220303082512-ba5bc0e589a3/go/src/io/ioutil/ioutil_test.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ioutil_test
     6  
     7  import (
     8  	"bytes"
     9  	. "io/ioutil"
    10  	"os"
    11  	"path/filepath"
    12  	"testing"
    13  )
    14  
    15  func checkSize(t *testing.T, path string, size int64) {
    16  	dir, err := os.Stat(path)
    17  	if err != nil {
    18  		t.Fatalf("Stat %q (looking for size %d): %s", path, size, err)
    19  	}
    20  	if dir.Size() != size {
    21  		t.Errorf("Stat %q: size %d want %d", path, dir.Size(), size)
    22  	}
    23  }
    24  
    25  func TestReadFile(t *testing.T) {
    26  	filename := "rumpelstilzchen"
    27  	contents, err := ReadFile(filename)
    28  	if err == nil {
    29  		t.Fatalf("ReadFile %s: error expected, none found", filename)
    30  	}
    31  
    32  	filename = "ioutil_test.go"
    33  	contents, err = ReadFile(filename)
    34  	if err != nil {
    35  		t.Fatalf("ReadFile %s: %v", filename, err)
    36  	}
    37  
    38  	checkSize(t, filename, int64(len(contents)))
    39  }
    40  
    41  func TestWriteFile(t *testing.T) {
    42  	f, err := TempFile("", "ioutil-test")
    43  	if err != nil {
    44  		t.Fatal(err)
    45  	}
    46  	filename := f.Name()
    47  	data := "Programming today is a race between software engineers striving to " +
    48  		"build bigger and better idiot-proof programs, and the Universe trying " +
    49  		"to produce bigger and better idiots. So far, the Universe is winning."
    50  
    51  	if err := WriteFile(filename, []byte(data), 0644); err != nil {
    52  		t.Fatalf("WriteFile %s: %v", filename, err)
    53  	}
    54  
    55  	contents, err := ReadFile(filename)
    56  	if err != nil {
    57  		t.Fatalf("ReadFile %s: %v", filename, err)
    58  	}
    59  
    60  	if string(contents) != data {
    61  		t.Fatalf("contents = %q\nexpected = %q", string(contents), data)
    62  	}
    63  
    64  	// cleanup
    65  	f.Close()
    66  	os.Remove(filename) // ignore error
    67  }
    68  
    69  func TestReadOnlyWriteFile(t *testing.T) {
    70  	if os.Getuid() == 0 {
    71  		t.Skipf("Root can write to read-only files anyway, so skip the read-only test.")
    72  	}
    73  
    74  	// We don't want to use TempFile directly, since that opens a file for us as 0600.
    75  	tempDir, err := TempDir("", t.Name())
    76  	if err != nil {
    77  		t.Fatalf("TempDir %s: %v", t.Name(), err)
    78  	}
    79  	defer os.RemoveAll(tempDir)
    80  	filename := filepath.Join(tempDir, "blurp.txt")
    81  
    82  	shmorp := []byte("shmorp")
    83  	florp := []byte("florp")
    84  	err = WriteFile(filename, shmorp, 0444)
    85  	if err != nil {
    86  		t.Fatalf("WriteFile %s: %v", filename, err)
    87  	}
    88  	err = WriteFile(filename, florp, 0444)
    89  	if err == nil {
    90  		t.Fatalf("Expected an error when writing to read-only file %s", filename)
    91  	}
    92  	got, err := ReadFile(filename)
    93  	if err != nil {
    94  		t.Fatalf("ReadFile %s: %v", filename, err)
    95  	}
    96  	if !bytes.Equal(got, shmorp) {
    97  		t.Fatalf("want %s, got %s", shmorp, got)
    98  	}
    99  }
   100  
   101  func TestReadDir(t *testing.T) {
   102  	dirname := "rumpelstilzchen"
   103  	_, err := ReadDir(dirname)
   104  	if err == nil {
   105  		t.Fatalf("ReadDir %s: error expected, none found", dirname)
   106  	}
   107  
   108  	dirname = ".."
   109  	list, err := ReadDir(dirname)
   110  	if err != nil {
   111  		t.Fatalf("ReadDir %s: %v", dirname, err)
   112  	}
   113  
   114  	foundFile := false
   115  	foundSubDir := false
   116  	for _, dir := range list {
   117  		switch {
   118  		case !dir.IsDir() && dir.Name() == "io_test.go":
   119  			foundFile = true
   120  		case dir.IsDir() && dir.Name() == "ioutil":
   121  			foundSubDir = true
   122  		}
   123  	}
   124  	if !foundFile {
   125  		t.Fatalf("ReadDir %s: io_test.go file not found", dirname)
   126  	}
   127  	if !foundSubDir {
   128  		t.Fatalf("ReadDir %s: ioutil directory not found", dirname)
   129  	}
   130  }