diff --git a/x/model/name_test.go b/x/model/name_test.go
index a4276e95..cae0861f 100644
--- a/x/model/name_test.go
+++ b/x/model/name_test.go
@@ -64,6 +64,17 @@ func TestNameParts(t *testing.T) {
 	}
 }
 
+func TestNamePartString(t *testing.T) {
+	if g := NamePartKind(-1).String(); g != "Unknown" {
+		t.Errorf("Unknown part = %q; want %q", g, "Unknown")
+	}
+	for kind, name := range kindNames {
+		if g := kind.String(); g != name {
+			t.Errorf("%s = %q; want %q", kind, g, name)
+		}
+	}
+}
+
 func TestPartTooLong(t *testing.T) {
 	for i := Host; i <= Build; i++ {
 		t.Run(i.String(), func(t *testing.T) {