Make fat32 ReadDir not return special volume label

Fixes #239

filesystem/fat32/fat32.go

@@ -493,9 +493,12 @@ func (fs *FileSystem) ReadDir(p string) ([]os.FileInfo, error) {
 	}
 	// once we have made it here, looping is done. We have found the final entry
 	// we need to return all of the file info
-	count := len(entries)
-	ret := make([]os.FileInfo, count)
-	for i, e := range entries {
+	//nolint:prealloc // because the following loop may omit some entry
+	var ret []os.FileInfo
+	for _, e := range entries {
+		if e.isVolumeLabel {
+			continue
+		}
 		shortName := e.filenameShort
 		if e.lowercaseShortname {
 			shortName = strings.ToLower(shortName)
@@ -507,13 +510,13 @@ func (fs *FileSystem) ReadDir(p string) ([]os.FileInfo, error) {
 		if fileExtension != "" {
 			shortName = fmt.Sprintf("%s.%s", shortName, fileExtension)
 		}
-		ret[i] = FileInfo{
+		ret = append(ret, FileInfo{
 			modTime:   e.modifyTime,
 			name:      e.filenameLong,
 			shortName: shortName,
 			size:      int64(e.fileSize),
 			isDir:     e.isSubdirectory,
-		}
+		})
 	}
 	return ret, nil
 }

filesystem/fat32/fat32_test.go

@@ -304,13 +304,12 @@ func TestFat32ReadDir(t *testing.T) {
 			isDir bool
 			err   error
 		}{
-			// should have 4 entries
-			//   <LABEL>
+			// should have 4 entries (Volume Label is not returned)
 			//   foo
 			//   TERCER~1
 			//   CORTO1.TXT
 			//   UNARCH~1.DAT
-			{"/", 5, "foo", true, nil},
+			{"/", 4, "foo", true, nil},
 			// should have 80 entries:
 			//  dir0-75 = 76 entries
 			//  dir     =  1 entry
@@ -589,7 +588,7 @@ func TestFat32OpenFile(t *testing.T) {
 			if err != nil {
 				t.Errorf("write many: error reading /: %v", err)
 			}
-			if len(dir) != fileCount+1 {
+			if len(dir) != fileCount {
 				t.Errorf("write many: entry count mismatch on /: expected %d, got %d -- %v", fileCount, len(dir), dir)
 			}
 		}