diff --git a/test/index.js b/test/index.js
index 2093ac7..57e4f56 100644
--- a/test/index.js
+++ b/test/index.js
@@ -335,7 +335,7 @@ suite ('ChainRec laws', () => {
   testLaws (laws.ChainRec (Z.equals, Either)) ({
     equivalence: [
       jsc.constant (x => x >= 1000),
-      jsc.constant (x => x <= 1 ? Left (String (x) + ' <= 1') : Right (x * x)),
+      jsc.constant (x => x <= 1 ? Left (show (x) + ' <= 1') : Right (x * x)),
       jsc.constant (Right),
       jsc.integer,
     ],