From 00d9b968d39cb4dc939f8052b4fa242080f7ce57 Mon Sep 17 00:00:00 2001
From: Whitney Young <wbyoung@fadingred.com>
Date: Sun, 4 Oct 2015 14:49:33 -0700
Subject: [PATCH] No longer silently allowing undefined method calls. Fixes
 #467.

---
 lib/chai/utils/overwriteMethod.js |  4 +++-
 test/utilities.js                 | 19 ++++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/lib/chai/utils/overwriteMethod.js b/lib/chai/utils/overwriteMethod.js
index 20657a57c..4c61c181e 100644
--- a/lib/chai/utils/overwriteMethod.js
+++ b/lib/chai/utils/overwriteMethod.js
@@ -42,7 +42,9 @@ var flag = require('./flag');
 
 module.exports = function (ctx, name, method) {
   var _method = ctx[name]
-    , _super = function () { return this; };
+    , _super = function () {
+      throw new Error(name + ' is not a function');
+    };
 
   if (_method && 'function' === typeof _method)
     _super = _method;
diff --git a/test/utilities.js b/test/utilities.js
index 66d6a8178..0fcae7c03 100644
--- a/test/utilities.js
+++ b/test/utilities.js
@@ -302,13 +302,30 @@ describe('utilities', function () {
         expect(_super).to.be.a('function');
         return function () {
           _.flag(this, 'doesnt', true);
-          _super.apply(this, arguments);
         }
       });
     });
 
     var dne = expect('something').to.doesnotexist();
     expect(dne.__flags).to.have.property('doesnt');
+
+    chai.use(function (_chai, _) {
+      expect(_chai.Assertion).to.not.respondTo('doesnotexistfail');
+      _chai.Assertion.overwriteMethod('doesnotexistfail', function (_super) {
+        expect(_super).to.be.a('function');
+        return function () {
+          _.flag(this, 'doesnt', true);
+          _super.apply(this, arguments);
+        }
+      });
+    });
+
+    var dneFail = expect('something');
+    var dneError;
+    try { dneFail.to.doesnotexistfail(); }
+    catch (e) { dneError = e; }
+    expect(dneFail.__flags).to.have.property('doesnt');
+    expect(dneError.message).to.eql('doesnotexistfail is not a function');
   });
 
   it('overwriteMethod returning result', function () {