github.com/gnolang/gno@v0.0.0-20240520182011-228e9d0192ce/tm2/pkg/os/tempfile_test.go (about)

     1  package os
     2  
     3  // Need access to internal variables, so can't use _test package
     4  
     5  import (
     6  	"bytes"
     7  	"fmt"
     8  	"os"
     9  	"testing"
    10  
    11  	"github.com/stretchr/testify/require"
    12  
    13  	"github.com/gnolang/gno/tm2/pkg/random"
    14  )
    15  
    16  func TestWriteFileAtomic(t *testing.T) {
    17  	var (
    18  		data             = []byte(random.RandStr(random.RandIntn(2048)))
    19  		old              = random.RandBytes(random.RandIntn(2048))
    20  		perm os.FileMode = 0o600
    21  	)
    22  
    23  	f, err := os.CreateTemp("/tmp", "write-atomic-test-")
    24  	if err != nil {
    25  		t.Fatal(err)
    26  	}
    27  	defer os.Remove(f.Name())
    28  
    29  	if err = os.WriteFile(f.Name(), old, 0o664); err != nil {
    30  		t.Fatal(err)
    31  	}
    32  
    33  	if err = WriteFileAtomic(f.Name(), data, perm); err != nil {
    34  		t.Fatal(err)
    35  	}
    36  
    37  	rData, err := os.ReadFile(f.Name())
    38  	if err != nil {
    39  		t.Fatal(err)
    40  	}
    41  
    42  	if !bytes.Equal(data, rData) {
    43  		t.Fatalf("data mismatch: %v != %v", data, rData)
    44  	}
    45  
    46  	stat, err := os.Stat(f.Name())
    47  	if err != nil {
    48  		t.Fatal(err)
    49  	}
    50  
    51  	if have, want := stat.Mode().Perm(), perm; have != want {
    52  		t.Errorf("have %v, want %v", have, want)
    53  	}
    54  }
    55  
    56  // This tests atomic write file when there is a single duplicate file.
    57  // Expected behavior is for a new file to be created, and the original write file to be unaltered.
    58  func TestWriteFileAtomicDuplicateFile(t *testing.T) {
    59  	var (
    60  		defaultSeed    uint64 = 1
    61  		testString            = "This is a glorious test string"
    62  		expectedString        = "Did the test file's string appear here?"
    63  
    64  		fileToWrite = "/tmp/TestWriteFileAtomicDuplicateFile-test.txt"
    65  	)
    66  	// Create a file at the seed, and reset the seed.
    67  	atomicWriteFileRand = defaultSeed
    68  	firstFileRand := randWriteFileSuffix()
    69  	atomicWriteFileRand = defaultSeed
    70  	fname := "/tmp/" + atomicWriteFilePrefix + firstFileRand
    71  	f, err := os.OpenFile(fname, atomicWriteFileFlag, 0o777)
    72  	defer os.Remove(fname)
    73  	// Defer here, in case there is a panic in WriteFileAtomic.
    74  	defer os.Remove(fileToWrite)
    75  
    76  	require.Nil(t, err)
    77  	f.WriteString(testString)
    78  	WriteFileAtomic(fileToWrite, []byte(expectedString), 0o777)
    79  	// Check that the first atomic file was untouched
    80  	firstAtomicFileBytes, err := os.ReadFile(fname)
    81  	require.Nil(t, err, "Error reading first atomic file")
    82  	require.Equal(t, []byte(testString), firstAtomicFileBytes, "First atomic file was overwritten")
    83  	// Check that the resultant file is correct
    84  	resultantFileBytes, err := os.ReadFile(fileToWrite)
    85  	require.Nil(t, err, "Error reading resultant file")
    86  	require.Equal(t, []byte(expectedString), resultantFileBytes, "Written file had incorrect bytes")
    87  
    88  	// Check that the intermediate write file was deleted
    89  	// Get the second write files' randomness
    90  	atomicWriteFileRand = defaultSeed
    91  	_ = randWriteFileSuffix()
    92  	secondFileRand := randWriteFileSuffix()
    93  	_, err = os.Stat("/tmp/" + atomicWriteFilePrefix + secondFileRand)
    94  	require.True(t, os.IsNotExist(err), "Intermittent atomic write file not deleted")
    95  }
    96  
    97  // This tests atomic write file when there are many duplicate files.
    98  // Expected behavior is for a new file to be created under a completely new seed,
    99  // and the original write files to be unaltered.
   100  func TestWriteFileAtomicManyDuplicates(t *testing.T) {
   101  	var (
   102  		defaultSeed    uint64 = 2
   103  		testString            = "This is a glorious test string, from file %d"
   104  		expectedString        = "Did any of the test file's string appear here?"
   105  
   106  		fileToWrite = "/tmp/TestWriteFileAtomicDuplicateFile-test.txt"
   107  	)
   108  	// Initialize all of the atomic write files
   109  	atomicWriteFileRand = defaultSeed
   110  	for i := 0; i < atomicWriteFileMaxNumConflicts+2; i++ {
   111  		fileRand := randWriteFileSuffix()
   112  		fname := "/tmp/" + atomicWriteFilePrefix + fileRand
   113  		f, err := os.OpenFile(fname, atomicWriteFileFlag, 0o777)
   114  		require.Nil(t, err)
   115  		f.WriteString(fmt.Sprintf(testString, i))
   116  		defer os.Remove(fname)
   117  	}
   118  
   119  	atomicWriteFileRand = defaultSeed
   120  	// Defer here, in case there is a panic in WriteFileAtomic.
   121  	defer os.Remove(fileToWrite)
   122  
   123  	WriteFileAtomic(fileToWrite, []byte(expectedString), 0o777)
   124  	// Check that all intermittent atomic file were untouched
   125  	atomicWriteFileRand = defaultSeed
   126  	for i := 0; i < atomicWriteFileMaxNumConflicts+2; i++ {
   127  		fileRand := randWriteFileSuffix()
   128  		fname := "/tmp/" + atomicWriteFilePrefix + fileRand
   129  		firstAtomicFileBytes, err := os.ReadFile(fname)
   130  		require.Nil(t, err, "Error reading first atomic file")
   131  		require.Equal(t, []byte(fmt.Sprintf(testString, i)), firstAtomicFileBytes,
   132  			"atomic write file %d was overwritten", i)
   133  	}
   134  
   135  	// Check that the resultant file is correct
   136  	resultantFileBytes, err := os.ReadFile(fileToWrite)
   137  	require.Nil(t, err, "Error reading resultant file")
   138  	require.Equal(t, []byte(expectedString), resultantFileBytes, "Written file had incorrect bytes")
   139  }