diff --git a/test/rustint/core_test.clj b/test/rustint/core_test.clj
index b73a1a3..a183086 100644
--- a/test/rustint/core_test.clj
+++ b/test/rustint/core_test.clj
@@ -79,3 +79,9 @@
     (is (= (compatibles? 'i64 [5.0]) true))
   )
 )
+
+(deftest compatibles-test04
+  (testing "Test 04 compatibles?"
+    (is (= (compatibles? 'f64 5.0) true))
+  )
+)