test(Subscriber): add test for no error propagation

Add test to assert that error happening in the next() handler should not propagate to the error()
handler.

For issue #1135.

spec/Subscriber-spec.js

@@ -7,4 +7,34 @@ describe('Subscriber', function () {
     var sub = new Subscriber();
     expect(sub[Rx.Symbol.rxSubscriber]()).toBe(sub);
   });
-});
+
+  describe('when created through create()', function () {
+    it('should not call error() if next() handler throws an error', function (done) {
+      var errorSpy = jasmine.createSpy('error');
+      var completeSpy = jasmine.createSpy('complete');
+
+      var subscriber = Subscriber.create(
+        function next(value) {
+          if (value === 2) {
+            throw 'error!';
+          }
+        },
+        errorSpy,
+        completeSpy
+      );
+
+      subscriber.next(1);
+      try {
+        subscriber.next(2);
+      } catch (err) {
+        expect(err).toEqual('error!');
+      }
+
+      setTimeout(function () {
+        expect(errorSpy).not.toHaveBeenCalled();
+        expect(completeSpy).not.toHaveBeenCalled();
+        done();
+      });
+    });
+  });
+});