correctly test and fix self fulfillment

browser/rsvp.js

@@ -479,7 +479,10 @@ define("rsvp/promise",
     EventTarget.mixin(Promise.prototype);
 
     function resolve(promise, value) {
-      if (objectOrFunction(value) && isFunction(value.then)) {
+
+      if (promise === value) {
+        fulfill(promise, value);
+      } else if (objectOrFunction(value) && isFunction(value.then)) {
         value.then(function(val) {
           if (value !== val) {
             resolve(promise, val);

browser/rsvp/promise.amd.js

@@ -115,7 +115,10 @@ define(
     EventTarget.mixin(Promise.prototype);
 
     function resolve(promise, value) {
-      if (objectOrFunction(value) && isFunction(value.then)) {
+
+      if (promise === value) {
+        fulfill(promise, value);
+      } else if (objectOrFunction(value) && isFunction(value.then)) {
         value.then(function(val) {
           if (value !== val) {
             resolve(promise, val);

lib/rsvp/promise.js

@@ -111,7 +111,10 @@ Promise.prototype = {
 EventTarget.mixin(Promise.prototype);
 
 function resolve(promise, value) {
-  if (objectOrFunction(value) && isFunction(value.then)) {
+
+  if (promise === value) {
+    fulfill(promise, value);
+  } else if (objectOrFunction(value) && isFunction(value.then)) {
     value.then(function(val) {
       if (value !== val) {
         resolve(promise, val);

tests/extension-tests.js

@@ -3,21 +3,25 @@ describe("RSVP extensions", function() {
   describe("self fulfillment", function(){
     it("treats self fulfillment as the recursive base case", function(done){
       var aDefer = new RSVP.defer(),
-      bDefer = new RSVP.defer();
+      bDefer = new RSVP.defer(),
+      promiseA = aDefer.promise,
+      promiseB = bDefer.promise;
 
-      aDefer.promise.then(function(a){
+      promiseA.then(function(a){
         setTimeout(function(){
-          bDefer.resolve(bDefer.promise);
+          bDefer.resolve(promiseB);
         }, 1);
 
-        return bDefer.promise;
+        return promiseB;
       });
 
-      bDefer.promise.then(function(c){
+      promiseB.then(function(c){
         done();
       })
 
-      aDefer.resolve(aDefer.promise);
+      aDefer.resolve(promiseA);
+    });
+  });
     });
   });