diff options
| -rw-r--r-- | doc/next/6-stdlib/99-minor/testing/fstest/63675.md | 4 | ||||
| -rw-r--r-- | src/testing/fstest/testfs.go | 69 | ||||
| -rw-r--r-- | src/testing/fstest/testfs_test.go | 38 |
3 files changed, 75 insertions, 36 deletions
diff --git a/doc/next/6-stdlib/99-minor/testing/fstest/63675.md b/doc/next/6-stdlib/99-minor/testing/fstest/63675.md new file mode 100644 index 0000000000..1a3552d50d --- /dev/null +++ b/doc/next/6-stdlib/99-minor/testing/fstest/63675.md @@ -0,0 +1,4 @@ +[`TestFS`](/pkg/testing/fstest#TestFS) now returns a structured +error that can be unwrapped (via method `Unwrap() []error`). This allows +inspecting errors using [`errors.Is`](/pkg/errors#Is) or +[`errors.As`](/pkg/errors#As). diff --git a/src/testing/fstest/testfs.go b/src/testing/fstest/testfs.go index 78b0b82640..0fd7d4806f 100644 --- a/src/testing/fstest/testfs.go +++ b/src/testing/fstest/testfs.go @@ -25,8 +25,8 @@ import ( // Otherwise, fsys must contain at least the listed files; it can also contain others. // The contents of fsys must not change concurrently with TestFS. // -// If TestFS finds any misbehaviors, it returns an error reporting all of them. -// The error text spans multiple lines, one per detected misbehavior. +// If TestFS finds any misbehaviors, it returns either the first error or a +// list of errors. Use [errors.Is] or [errors.As] to inspect. // // Typical usage inside a test is: // @@ -51,7 +51,7 @@ func TestFS(fsys fs.FS, expected ...string) error { return err } if err := testFS(sub, subExpected...); err != nil { - return fmt.Errorf("testing fs.Sub(fsys, %s): %v", dir, err) + return fmt.Errorf("testing fs.Sub(fsys, %s): %w", dir, err) } break // one sub-test is enough } @@ -89,32 +89,29 @@ func testFS(fsys fs.FS, expected ...string) error { t.errorf("expected but not found: %s", name) } } - if len(t.errText) == 0 { + if len(t.errors) == 0 { return nil } - return errors.New("TestFS found errors:\n" + string(t.errText)) + return fmt.Errorf("TestFS found errors:\n%w", errors.Join(t.errors...)) } // An fsTester holds state for running the test. type fsTester struct { - fsys fs.FS - errText []byte - dirs []string - files []string + fsys fs.FS + errors []error + dirs []string + files []string } -// errorf adds an error line to errText. +// errorf adds an error to the list of errors. func (t *fsTester) errorf(format string, args ...any) { - if len(t.errText) > 0 { - t.errText = append(t.errText, '\n') - } - t.errText = append(t.errText, fmt.Sprintf(format, args...)...) + t.errors = append(t.errors, fmt.Errorf(format, args...)) } func (t *fsTester) openDir(dir string) fs.ReadDirFile { f, err := t.fsys.Open(dir) if err != nil { - t.errorf("%s: Open: %v", dir, err) + t.errorf("%s: Open: %w", dir, err) return nil } d, ok := f.(fs.ReadDirFile) @@ -138,7 +135,7 @@ func (t *fsTester) checkDir(dir string) { list, err := d.ReadDir(-1) if err != nil { d.Close() - t.errorf("%s: ReadDir(-1): %v", dir, err) + t.errorf("%s: ReadDir(-1): %w", dir, err) return } @@ -176,7 +173,7 @@ func (t *fsTester) checkDir(dir string) { list2, err := d.ReadDir(-1) if len(list2) > 0 || err != nil { d.Close() - t.errorf("%s: ReadDir(-1) at EOF = %d entries, %v, wanted 0 entries, nil", dir, len(list2), err) + t.errorf("%s: ReadDir(-1) at EOF = %d entries, %w, wanted 0 entries, nil", dir, len(list2), err) return } @@ -184,13 +181,13 @@ func (t *fsTester) checkDir(dir string) { list2, err = d.ReadDir(1) if len(list2) > 0 || err != io.EOF { d.Close() - t.errorf("%s: ReadDir(1) at EOF = %d entries, %v, wanted 0 entries, EOF", dir, len(list2), err) + t.errorf("%s: ReadDir(1) at EOF = %d entries, %w, wanted 0 entries, EOF", dir, len(list2), err) return } // Check that close does not report an error. if err := d.Close(); err != nil { - t.errorf("%s: Close: %v", dir, err) + t.errorf("%s: Close: %w", dir, err) } // Check that closing twice doesn't crash. @@ -204,7 +201,7 @@ func (t *fsTester) checkDir(dir string) { defer d.Close() list2, err = d.ReadDir(-1) if err != nil { - t.errorf("%s: second Open+ReadDir(-1): %v", dir, err) + t.errorf("%s: second Open+ReadDir(-1): %w", dir, err) return } t.checkDirList(dir, "first Open+ReadDir(-1) vs second Open+ReadDir(-1)", list, list2) @@ -230,7 +227,7 @@ func (t *fsTester) checkDir(dir string) { break } if err != nil { - t.errorf("%s: third Open: ReadDir(%d) after %d: %v", dir, n, len(list2), err) + t.errorf("%s: third Open: ReadDir(%d) after %d: %w", dir, n, len(list2), err) return } if n == 0 { @@ -244,7 +241,7 @@ func (t *fsTester) checkDir(dir string) { if fsys, ok := t.fsys.(fs.ReadDirFS); ok { list2, err := fsys.ReadDir(dir) if err != nil { - t.errorf("%s: fsys.ReadDir: %v", dir, err) + t.errorf("%s: fsys.ReadDir: %w", dir, err) return } t.checkDirList(dir, "first Open+ReadDir(-1) vs fsys.ReadDir", list, list2) @@ -259,7 +256,7 @@ func (t *fsTester) checkDir(dir string) { // Check fs.ReadDir as well. list2, err = fs.ReadDir(t.fsys, dir) if err != nil { - t.errorf("%s: fs.ReadDir: %v", dir, err) + t.errorf("%s: fs.ReadDir: %w", dir, err) return } t.checkDirList(dir, "first Open+ReadDir(-1) vs fs.ReadDir", list, list2) @@ -358,7 +355,7 @@ func (t *fsTester) checkGlob(dir string, list []fs.DirEntry) { names, err := t.fsys.(fs.GlobFS).Glob(glob) if err != nil { - t.errorf("%s: Glob(%#q): %v", dir, glob, err) + t.errorf("%s: Glob(%#q): %w", dir, glob, err) return } if reflect.DeepEqual(want, names) { @@ -391,13 +388,13 @@ func (t *fsTester) checkGlob(dir string, list []fs.DirEntry) { func (t *fsTester) checkStat(path string, entry fs.DirEntry) { file, err := t.fsys.Open(path) if err != nil { - t.errorf("%s: Open: %v", path, err) + t.errorf("%s: Open: %w", path, err) return } info, err := file.Stat() file.Close() if err != nil { - t.errorf("%s: Stat: %v", path, err) + t.errorf("%s: Stat: %w", path, err) return } fentry := formatEntry(entry) @@ -409,7 +406,7 @@ func (t *fsTester) checkStat(path string, entry fs.DirEntry) { einfo, err := entry.Info() if err != nil { - t.errorf("%s: entry.Info: %v", path, err) + t.errorf("%s: entry.Info: %w", path, err) return } finfo := formatInfo(info) @@ -430,7 +427,7 @@ func (t *fsTester) checkStat(path string, entry fs.DirEntry) { // Stat should be the same as Open+Stat, even for symlinks. info2, err := fs.Stat(t.fsys, path) if err != nil { - t.errorf("%s: fs.Stat: %v", path, err) + t.errorf("%s: fs.Stat: %w", path, err) return } finfo2 := formatInfo(info2) @@ -441,7 +438,7 @@ func (t *fsTester) checkStat(path string, entry fs.DirEntry) { if fsys, ok := t.fsys.(fs.StatFS); ok { info2, err := fsys.Stat(path) if err != nil { - t.errorf("%s: fsys.Stat: %v", path, err) + t.errorf("%s: fsys.Stat: %w", path, err) return } finfo2 := formatInfo(info2) @@ -508,19 +505,19 @@ func (t *fsTester) checkFile(file string) { // Read entire file. f, err := t.fsys.Open(file) if err != nil { - t.errorf("%s: Open: %v", file, err) + t.errorf("%s: Open: %w", file, err) return } data, err := io.ReadAll(f) if err != nil { f.Close() - t.errorf("%s: Open+ReadAll: %v", file, err) + t.errorf("%s: Open+ReadAll: %w", file, err) return } if err := f.Close(); err != nil { - t.errorf("%s: Close: %v", file, err) + t.errorf("%s: Close: %w", file, err) } // Check that closing twice doesn't crash. @@ -531,7 +528,7 @@ func (t *fsTester) checkFile(file string) { if fsys, ok := t.fsys.(fs.ReadFileFS); ok { data2, err := fsys.ReadFile(file) if err != nil { - t.errorf("%s: fsys.ReadFile: %v", file, err) + t.errorf("%s: fsys.ReadFile: %w", file, err) return } t.checkFileRead(file, "ReadAll vs fsys.ReadFile", data, data2) @@ -543,7 +540,7 @@ func (t *fsTester) checkFile(file string) { } data2, err = fsys.ReadFile(file) if err != nil { - t.errorf("%s: second call to fsys.ReadFile: %v", file, err) + t.errorf("%s: second call to fsys.ReadFile: %w", file, err) return } t.checkFileRead(file, "Readall vs second fsys.ReadFile", data, data2) @@ -555,7 +552,7 @@ func (t *fsTester) checkFile(file string) { // Check that fs.ReadFile works with t.fsys. data2, err := fs.ReadFile(t.fsys, file) if err != nil { - t.errorf("%s: fs.ReadFile: %v", file, err) + t.errorf("%s: fs.ReadFile: %w", file, err) return } t.checkFileRead(file, "ReadAll vs fs.ReadFile", data, data2) @@ -563,7 +560,7 @@ func (t *fsTester) checkFile(file string) { // Use iotest.TestReader to check small reads, Seek, ReadAt. f, err = t.fsys.Open(file) if err != nil { - t.errorf("%s: second Open: %v", file, err) + t.errorf("%s: second Open: %w", file, err) return } defer f.Close() diff --git a/src/testing/fstest/testfs_test.go b/src/testing/fstest/testfs_test.go index a48c597ff4..b9f10c613a 100644 --- a/src/testing/fstest/testfs_test.go +++ b/src/testing/fstest/testfs_test.go @@ -5,6 +5,7 @@ package fstest import ( + "errors" "internal/testenv" "io/fs" "os" @@ -76,3 +77,40 @@ func TestShuffledFS(t *testing.T) { t.Error(err) } } + +// failPermFS is a filesystem that always fails with fs.ErrPermission. +type failPermFS struct{} + +func (f failPermFS) Open(name string) (fs.File, error) { + if !fs.ValidPath(name) { + return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrInvalid} + } + return nil, &fs.PathError{Op: "open", Path: name, Err: fs.ErrPermission} +} + +func TestTestFSWrappedErrors(t *testing.T) { + err := TestFS(failPermFS{}) + if err == nil { + t.Fatal("error expected") + } + t.Logf("Error (expecting wrapped fs.ErrPermission):\n%v", err) + + if !errors.Is(err, fs.ErrPermission) { + t.Errorf("error should be a wrapped ErrPermission: %#v", err) + } + + // TestFS is expected to return a list of errors. + // Enforce that the list can be extracted for browsing. + var errs interface{ Unwrap() []error } + if !errors.As(err, &errs) { + t.Errorf("caller should be able to extract the errors as a list: %#v", err) + } else { + for _, err := range errs.Unwrap() { + // ErrPermission is expected + // but any other error must be reported. + if !errors.Is(err, fs.ErrPermission) { + t.Errorf("unexpected error: %v", err) + } + } + } +} |