diff --git a/lib/createStandardErrorMessage.js b/lib/createStandardErrorMessage.js
index <HASH>..<HASH> 100644
--- a/lib/createStandardErrorMessage.js
+++ b/lib/createStandardErrorMessage.js
@@ -13,16 +13,14 @@ module.exports = function createStandardErrorMessage(output, subject, testDescri
             assertionIndices.push(offset + parsed.args.length - 2);
             var assertionName = options.originalArgs[offset + parsed.args.length - 2];
             var assertions = options.unexpected.assertions[assertionName];
-            var assertion;
-            for (var j = 0 ; j < assertions.length ; j += 1) {
-                if (assertions[j].parsed.args.some(function (a) { return a.isAssertion; })) {
-                    assertion = assertions[j];
-                    break;
+            if (assertions) {
+                for (var j = 0 ; j < assertions.length ; j += 1) {
+                    if (assertions[j].parsed.args.some(function (a) { return a.isAssertion; })) {
+                        markAssertionIndices(assertions[j].parsed, offset + parsed.args.length - 1);
+                        break;
+                    }
                 }
             }
-            if (assertion) {
-                markAssertionIndices(assertion.parsed, offset + parsed.args.length - 1);
-            }
         }
     }
createStandardErrorMessage: Don't break when the assertion pointed to by the argument declared <assertion> does not exist.