diff --git a/parse.go b/parse.go
index 59326c1..508f6b5 100644
--- a/parse.go
+++ b/parse.go
@@ -9,6 +9,8 @@ import (
 )
 
 var errUnsupportedListLine = errors.New("unsupported LIST line")
+var errUnsupportedListDate = errors.New("unsupported LIST date")
+var errUnknownListEntryType = errors.New("unknown entry type")
 
 type parseFunc func(string, time.Time, *time.Location) (*Entry, error)
 
@@ -132,7 +134,7 @@ func parseLsListLine(line string, now time.Time, loc *time.Location) (*Entry, er
 	case 'l':
 		e.Type = EntryTypeLink
 	default:
-		return nil, errors.New("unknown entry type")
+		return nil, errUnknownListEntryType
 	}
 
 	if err := e.setTime(fields[5:8], now, loc); err != nil {
@@ -246,7 +248,7 @@ func (e *Entry) setTime(fields []string, now time.Time, loc *time.Location) (err
 
 	} else { // only the date
 		if len(fields[2]) != 4 {
-			return errors.New("invalid year format in time string")
+			return errUnsupportedListDate
 		}
 		timeStr := fmt.Sprintf("%s %s %s 00:00", fields[1], fields[0], fields[2])
 		e.Time, err = time.ParseInLocation("_2 Jan 2006 15:04", timeStr, loc)
diff --git a/parse_test.go b/parse_test.go
index 93edd42..7980185 100644
--- a/parse_test.go
+++ b/parse_test.go
@@ -24,7 +24,7 @@ type line struct {
 
 type unsupportedLine struct {
 	line string
-	err  string
+	err  error
 }
 
 var listTests = []line{
@@ -72,14 +72,14 @@ var listTests = []line{
 
 // Not supported, we expect a specific error message
 var listTestsFail = []unsupportedLine{
-	{"d [R----F--] supervisor            512       Jan 16 18:53 login", "Unsupported LIST line"},
-	{"- [R----F--] rhesus             214059       Oct 20 15:27 cx.exe", "Unsupported LIST line"},
-	{"drwxr-xr-x    3 110      1002            3 Dec 02  209 pub", "Invalid year format in time string"},
-	{"modify=20150806235817;invalid;UNIX.owner=0; movies", "Unsupported LIST line"},
-	{"Zrwxrwxrwx   1 root     other          7 Jan 25 00:17 bin -> usr/bin", "Unknown entry type"},
-	{"total 1", "Unsupported LIST line"},
-	{"000000000x ", "Unsupported LIST line"}, // see https://github.com/jlaffaye/ftp/issues/97
-	{"", "Unsupported LIST line"},
+	{"d [R----F--] supervisor            512       Jan 16 18:53 login", errUnsupportedListLine},
+	{"- [R----F--] rhesus             214059       Oct 20 15:27 cx.exe", errUnsupportedListLine},
+	{"drwxr-xr-x    3 110      1002            3 Dec 02  209 pub", errUnsupportedListDate},
+	{"modify=20150806235817;invalid;UNIX.owner=0; movies", errUnsupportedListLine},
+	{"Zrwxrwxrwx   1 root     other          7 Jan 25 00:17 bin -> usr/bin", errUnknownListEntryType},
+	{"total 1", errUnsupportedListLine},
+	{"000000000x ", errUnsupportedListLine}, // see https://github.com/jlaffaye/ftp/issues/97
+	{"", errUnsupportedListLine},
 }
 
 func TestParseValidListLine(t *testing.T) {
@@ -110,8 +110,8 @@ func TestParseUnsupportedListLine(t *testing.T) {
 		if err == nil {
 			t.Errorf("parseListLine(%v) expected to fail", lt.line)
 		}
-		if err.Error() != lt.err {
-			t.Errorf("parseListLine(%v) expected to fail with error: '%s'; was: '%s'", lt.line, lt.err, err.Error())
+		if err != lt.err {
+			t.Errorf("parseListLine(%v) expected to fail with error: '%s'; was: '%s'", lt.line, lt.err.Error(), err.Error())
 		}
 	}
 }