bugfix(assertAsync): add promiseLike support for angularJS promises

implement a promiseLike method so libraries using non-browser promise
implementations can still utilize assertAsync functionality.

Fixes: #1612

spec/core/UtilSpec.js

@@ -31,6 +31,105 @@ describe("jasmineUnderTest.util", function() {
     });
   });
 
+  describe("promise utils", function () {
+
+    var mockNativePromise,
+      mockPromiseLikeObject;
+
+    var mockPromiseLike = function () {this.then = function () {};};
+
+    beforeEach(function () {
+      jasmine.getEnv().requirePromises();
+      mockNativePromise = new Promise(function (res, rej) {});
+      mockPromiseLikeObject = new mockPromiseLike();
+    });
+
+    describe("isPromise", function () {
+
+      it("should return true when passed a native promise", function () {
+        expect(jasmineUnderTest.isPromise(mockNativePromise)).toBe(true);
+      });
+
+      it("should return false for promise like objects", function () {
+        expect(jasmineUnderTest.isPromise(mockPromiseLikeObject)).toBe(false);
+      });
+
+      it("should return false for strings", function () {
+        expect(jasmineUnderTest.isPromise("hello")).toBe(false);
+      });
+
+      it("should return false for numbers", function () {
+        expect(jasmineUnderTest.isPromise(3)).toBe(false);
+      });
+
+      it("should return false for null", function () {
+        expect(jasmineUnderTest.isPromise(null)).toBe(false);
+      });
+
+      it("should return false for undefined", function () {
+        expect(jasmineUnderTest.isPromise(undefined)).toBe(false);
+      });
+
+      it("should return false for arrays", function () {
+        expect(jasmineUnderTest.isPromise([])).toBe(false);
+      });
+
+      it("should return false for objects", function () {
+        expect(jasmineUnderTest.isPromise({})).toBe(false);
+      });
+
+      it("should return false for boolean values", function () {
+        expect(jasmineUnderTest.isPromise(true)).toBe(false);
+      });
+
+    });
+
+    describe("isPromiseLike", function () {
+
+      it("should return true when passed a native promise", function () {
+        expect(jasmineUnderTest.isPromiseLike(mockNativePromise)).toBe(true);
+      });
+
+      it("should return  true for promise like objects", function () {
+        expect(jasmineUnderTest.isPromiseLike(mockPromiseLikeObject)).toBe(true);
+      });
+
+      it("should return false if then is not a function", function () {
+        expect(jasmineUnderTest.isPromiseLike({then:{its:"Not a function :O"}})).toBe(false);
+      });
+
+      it("should return false for strings", function () {
+        expect(jasmineUnderTest.isPromiseLike("hello")).toBe(false);
+      });
+
+      it("should return false for numbers", function () {
+        expect(jasmineUnderTest.isPromiseLike(3)).toBe(false);
+      });
+
+      it("should return false for null", function () {
+        expect(jasmineUnderTest.isPromiseLike(null)).toBe(false);
+      });
+
+      it("should return false for undefined", function () {
+        expect(jasmineUnderTest.isPromiseLike(undefined)).toBe(false);
+      });
+
+      it("should return false for arrays", function () {
+        expect(jasmineUnderTest.isPromiseLike([])).toBe(false);
+      });
+
+      it("should return false for objects", function () {
+        expect(jasmineUnderTest.isPromiseLike({})).toBe(false);
+      });
+
+      it("should return false for boolean values", function () {
+        expect(jasmineUnderTest.isPromiseLike(true)).toBe(false);
+      });
+
+    });
+
+  });
+
   describe("isUndefined", function() {
     it("reports if a variable is defined", function() {
       var a;

src/core/AsyncExpectation.js

@@ -19,7 +19,7 @@ getJasmineRequireObj().AsyncExpectation = function(j$) {
       throw new Error('expectAsync is unavailable because the environment does not support promises.');
     }
 
-    if (!j$.isPromise(this.actual)) {
+    if (!j$.isPromiseLike(this.actual)) {
       throw new Error('Expected expectAsync to be called with a promise.');
     }
 

src/core/base.js

@@ -120,7 +120,11 @@ getJasmineRequireObj().base = function(j$, jasmineGlobal) {
   };
 
   j$.isPromise = function(obj) {
-    return typeof jasmineGlobal.Promise !== 'undefined' && obj && obj.constructor === jasmineGlobal.Promise;
+    return typeof jasmineGlobal.Promise !== 'undefined' && !!obj && obj.constructor === jasmineGlobal.Promise;
+  };
+
+  j$.isPromiseLike = function(obj) {
+    return !!obj && j$.isFunction_(obj.then);
   };
 
   j$.fnNameFor = function(func) {