diff --git a/assert/Asserter_test.go b/assert/Asserter_test.go
index c63c0af..05bb530 100644
--- a/assert/Asserter_test.go
+++ b/assert/Asserter_test.go
@@ -1137,6 +1137,8 @@ func TestAsserter_Contain_stringHasSub(t *testing.T) {
 		IsFailed bool
 	}
 
+	type Str string
+
 	for _, tc := range []TestCase{
 		{
 			Desc:     "when doesn't have sub",
@@ -1162,6 +1164,12 @@ func TestAsserter_Contain_stringHasSub(t *testing.T) {
 			Sub:      "world!",
 			IsFailed: false,
 		},
+		{
+			Desc:     "when string based type has subset of a primite string",
+			String:   Str("foo-bar-baz"),
+			Sub:      "bar",
+			IsFailed: false,
+		},
 	} {
 		t.Run(tc.Desc, AssertContainsTestCase(tc.String, tc.Sub, tc.IsFailed))
 	}