Add Chmod and expand a test

Author: cmaglie

Diff for: paths.go

@@ -418,6 +418,13 @@ func (p *Path) CopyDirTo(dst *Path) error {
 	return nil
 }
 
+// Chmod changes the mode of the named file to mode. If the file is a
+// symbolic link, it changes the mode of the link's target. If there
+// is an error, it will be of type *os.PathError.
+func (p *Path) Chmod(mode fs.FileMode) error {
+	return os.Chmod(p.path, mode)
+}
+
 // Chtimes changes the access and modification times of the named file,
 // similar to the Unix utime() or utimes() functions.
 func (p *Path) Chtimes(atime, mtime time.Time) error {

Diff for: readdir_test.go

@@ -31,6 +31,7 @@ package paths
 
 import (
 	"fmt"
+	"io/fs"
 	"os"
 	"testing"
 	"time"
@@ -317,4 +318,25 @@ func TestReadDirRecursiveLoopDetection(t *testing.T) {
 		pathEqualsTo(t, "testdata/loops/regular_3/dir2/file2", l[5])
 		pathEqualsTo(t, "testdata/loops/regular_3/link", l[6]) // broken symlink is reported in files
 	}
+
+	{
+		dir1 := loopsPath.Join("regular_4_with_permission_error", "dir1")
+
+		l, err := unbuondedReaddir("regular_4_with_permission_error")
+		require.NoError(t, err)
+		require.NotEmpty(t, l)
+
+		dir1Stat, err := dir1.Stat()
+		require.NoError(t, err)
+		err = dir1.Chmod(fs.FileMode(0)) // Enforce permission error
+		require.NoError(t, err)
+		t.Cleanup(func() {
+			// Restore normal permission after the test
+			dir1.Chmod(dir1Stat.Mode())
+		})
+
+		l, err = unbuondedReaddir("regular_4_with_permission_error")
+		require.Error(t, err)
+		require.Nil(t, l)
+	}
 }

Diff for: testdata/loops/regular_4_with_permission_error/dir1/file1

@@ -0,0 +1 @@
+broken