testfs_test.go

Documentation: testing/fstest

     1  // Copyright 2021 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 fstest
     6  
     7  import (
     8  	"errors"
     9  	"internal/testenv"
    10  	"io/fs"
    11  	"os"
    12  	"path/filepath"
    13  	"slices"
    14  	"strings"
    15  	"testing"
    16  )
    17  
    18  func TestSymlink(t *testing.T) {
    19  	testenv.MustHaveSymlink(t)
    20  
    21  	tmp := t.TempDir()
    22  	tmpfs := os.DirFS(tmp)
    23  
    24  	if err := os.WriteFile(filepath.Join(tmp, "hello"), []byte("hello, world\n"), 0644); err != nil {
    25  		t.Fatal(err)
    26  	}
    27  
    28  	if err := os.Symlink(filepath.Join(tmp, "hello"), filepath.Join(tmp, "hello.link")); err != nil {
    29  		t.Fatal(err)
    30  	}
    31  
    32  	if err := TestFS(tmpfs, "hello", "hello.link"); err != nil {
    33  		t.Fatal(err)
    34  	}
    35  }
    36  
    37  func TestDash(t *testing.T) {
    38  	m := MapFS{
    39  		"a-b/a": {Data: []byte("a-b/a")},
    40  	}
    41  	if err := TestFS(m, "a-b/a"); err != nil {
    42  		t.Error(err)
    43  	}
    44  }
    45  
    46  type shuffledFS MapFS
    47  
    48  func (fsys shuffledFS) Open(name string) (fs.File, error) {
    49  	f, err := MapFS(fsys).Open(name)
    50  	if err != nil {
    51  		return nil, err
    52  	}
    53  	return &shuffledFile{File: f}, nil
    54  }
    55  
    56  type shuffledFile struct{ fs.File }
    57  
    58  func (f *shuffledFile) ReadDir(n int) ([]fs.DirEntry, error) {
    59  	dirents, err := f.File.(fs.ReadDirFile).ReadDir(n)
    60  	// Shuffle in a deterministic way, all we care about is making sure that the
    61  	// list of directory entries is not is the lexicographic order.
    62  	//
    63  	// We do this to make sure that the TestFS test suite is not affected by the
    64  	// order of directory entries.
    65  	slices.SortFunc(dirents, func(a, b fs.DirEntry) int {
    66  		return strings.Compare(b.Name(), a.Name())
    67  	})
    68  	return dirents, err
    69  }
    70  
    71  func TestShuffledFS(t *testing.T) {
    72  	fsys := shuffledFS{
    73  		"tmp/one":   {Data: []byte("1")},
    74  		"tmp/two":   {Data: []byte("2")},
    75  		"tmp/three": {Data: []byte("3")},
    76  	}
    77  	if err := TestFS(fsys, "tmp/one", "tmp/two", "tmp/three"); err != nil {
    78  		t.Error(err)
    79  	}
    80  }
    81  
    82  // failPermFS is a filesystem that always fails with fs.ErrPermission.
    83  type failPermFS struct{}
    84  
    85  func (f failPermFS) Open(name string) (fs.File, error) {
    86  	if !fs.ValidPath(name) {
    87  		return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid}
    88  	}
    89  	return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrPermission}
    90  }
    91  
    92  func TestTestFSWrappedErrors(t *testing.T) {
    93  	err := TestFS(failPermFS{})
    94  	if err == nil {
    95  		t.Fatal("error expected")
    96  	}
    97  	t.Logf("Error (expecting wrapped fs.ErrPermission):\n%v", err)
    98  
    99  	if !errors.Is(err, fs.ErrPermission) {
   100  		t.Errorf("error should be a wrapped ErrPermission: %#v", err)
   101  	}
   102  
   103  	// TestFS is expected to return a list of errors.
   104  	// Enforce that the list can be extracted for browsing.
   105  	var errs interface{ Unwrap() []error }
   106  	if !errors.As(err, &errs) {
   107  		t.Errorf("caller should be able to extract the errors as a list: %#v", err)
   108  	} else {
   109  		for _, err := range errs.Unwrap() {
   110  			// ErrPermission is expected
   111  			// but any other error must be reported.
   112  			if !errors.Is(err, fs.ErrPermission) {
   113  				t.Errorf("unexpected error: %v", err)
   114  			}
   115  		}
   116  	}
   117  }
   118
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