diff --git a/test/clj_jtwig/core_test.clj b/test/clj_jtwig/core_test.clj
index ee144b5..66015b2 100644
--- a/test/clj_jtwig/core_test.clj
+++ b/test/clj_jtwig/core_test.clj
@@ -14,6 +14,14 @@
 ; Some of the variable passing and return / iteration verification tests might be a bit
 ; overkill, but better safe than sorry. :)
 
+; TODO: is there a better way to test that something is an instance of some object generated by reify?
+(defn valid-function-handler? [x]
+  (and (not (nil? x))
+       (-> x
+           (class)
+           (.getName)
+           (.startsWith "clj_jtwig.core$add_function"))))
+
 (deftest string-template
   (testing "Evaluating templates in string vars"
     (is (= (render "Hello {{ name }}!"
@@ -123,8 +131,9 @@
     (do
       (reset-functions!)
 
-      (is (nil? (deftwigfn "add" [a b]
-                  (+ a b))))
+      (is (valid-function-handler?
+            (deftwigfn "add" [a b]
+              (+ a b))))
 
       (is (true? (function-exists? "add")))
       (is (false? (function-exists? "foobar")))
@@ -150,11 +159,13 @@
     (do
       (reset-functions!)
 
-      (is (nil? (deftwigfn "add2" [a b]
-                  (+ a b))))
+      (is (valid-function-handler?
+            (deftwigfn "add2" [a b]
+              (+ a b))))
       (is (true? (function-exists? "add2")))
-      (is (nil? (deftwigfn "addAll" [& numbers]
-                  (apply + numbers))))
+      (is (valid-function-handler?
+            (deftwigfn "addAll" [& numbers]
+              (apply + numbers))))
       (is (true? (function-exists? "addAll")))
 
       (is (= (render "{{add2(1, 2)}}" nil)
@@ -176,11 +187,13 @@
     (do
       (reset-functions!)
 
-      (is (nil? (deftwigfn "identity" [x]
-                  x)))
+      (is (valid-function-handler?
+            (deftwigfn "identity" [x]
+              x)))
       (is (true? (function-exists? "identity")))
-      (is (nil? (deftwigfn "typename" [x]
-                  (.getName (type x)))))
+      (is (valid-function-handler?
+            (deftwigfn "typename" [x]
+              (.getName (type x)))))
       (is (true? (function-exists? "typename")))
 
       ; verify that the clojure function recognizes the correct types when the variable is passed via the model-map