From a0b2f1af5a0a9b1820e8d82da69a39e8d6c7dac5 Mon Sep 17 00:00:00 2001
From: Sarun Rattanasiri <midnight_w@gmx.tw>
Date: Sun, 2 Apr 2017 18:44:46 +0700
Subject: [PATCH] test(fromPromise): ensure Observables can be created from
 other promise implementations

---
 spec/observables/from-promise-spec.ts | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/spec/observables/from-promise-spec.ts b/spec/observables/from-promise-spec.ts
index 49e64c7d940..7fc74fe5339 100644
--- a/spec/observables/from-promise-spec.ts
+++ b/spec/observables/from-promise-spec.ts
@@ -72,6 +72,26 @@ describe('Observable.fromPromise', () => {
     });
   });
 
+  it('should accept PromiseLike object for interoperability', (done: MochaDone) => {
+    class CustomPromise<T> implements PromiseLike<T> {
+      constructor(private promise: PromiseLike<T>) {
+      }
+      then(onFulfilled?: ((value: T) => (PromiseLike<T> | T)) | any | any,
+           onRejected?: ((reason: any) => (PromiseLike<T> | T)) | any | any): PromiseLike<T> {
+               return new CustomPromise(this.promise.then(onFulfilled, onRejected));
+      };
+    }
+    const promise = new CustomPromise(Promise.resolve(42));
+    Observable.fromPromise(promise)
+      .subscribe(
+        (x: number) => { expect(x).to.equal(42); },
+        () => {
+          done(new Error('should not be called'));
+        }, () => {
+          done();
+        });
+  });
+
   it('should emit a value from a resolved promise on a separate scheduler', (done: MochaDone) => {
     const promise = Promise.resolve(42);
     Observable.fromPromise(promise, Rx.Scheduler.asap)