Merge pull request #178 from pretenderjs/warn-on-second-pretender

Warn on second pretender

pretender.js

@@ -121,7 +121,7 @@ function Pretender(/* routeMap1, routeMap2, ...*/) {
 
   // capture xhr requests, channeling them into
   // the route map.
-  self.XMLHttpRequest = interceptor(this);
+  self.XMLHttpRequest = interceptor(this, this._nativeXMLHttpRequest);
 
   // 'start' the server
   this.running = true;
@@ -132,7 +132,7 @@ function Pretender(/* routeMap1, routeMap2, ...*/) {
   }
 }
 
-function interceptor(pretender) {
+function interceptor(pretender, nativeRequest) {
   function FakeRequest() {
     // super()
     FakeXMLHttpRequest.call(this);
@@ -259,6 +259,12 @@ function interceptor(pretender) {
   };
 
   FakeRequest.prototype = proto;
+
+  if (nativeRequest.prototype._passthroughCheck) {
+    throw new Error('You created a second Pretender instance while there was already one running. ' +
+          'Running two Pretender servers at once will lead to unexpected results!' +
+          'Please call .shutdown() on your instances when you no longer need them to respond.');
+  }
   return FakeRequest;
 }
 

test/creation_test.js

@@ -2,6 +2,26 @@ var pretender;
 var describe = QUnit.module;
 var it = QUnit.test;
 
+describe('pretender creation - without shutdown', function(config) {
+  var secondPretender;
+
+  config.beforeEach(function() {
+    pretender = new Pretender();
+  });
+
+  config.afterEach(function() {
+    pretender.shutdown();
+  });
+
+  test('an error is thrown when you start a new pretender while another one is running', function(assert) {
+    var message = 'You created a second Pretender instance while there ' +
+                  'already one running. Running two Pretender servers at once will lead to unexpected results!';
+    assert.throws(function() {
+      new Pretender();
+    }, message);
+  });
+});
+
 describe('pretender creation', function(config) {
   config.afterEach(function() {
     if (pretender) {
@@ -55,3 +75,4 @@ describe('pretender creation', function(config) {
   });
 });
 
+