diff --git a/test/rustint/core_test.clj b/test/rustint/core_test.clj
index 0560ac4..804be2a 100644
--- a/test/rustint/core_test.clj
+++ b/test/rustint/core_test.clj
@@ -115,3 +115,9 @@
     (is (= (compatibles? 'char \a) true))
   )
 )
+
+(deftest compatibles-test10
+  (testing "Test 10 compatibles?"
+    (is (= (compatibles? 'char 'a) false))
+  )
+)