Check that Promise subclasses have callable resolve/reject

test/mjsunit/es6/debug-promises/throw-with-undefined-reject.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// Flags: --expose-debug-as debug --allow-natives-syntax --promise-extra
-
-// Test debug events when an exception is thrown inside a Promise, which is

[adamk, 2016/03/10 02:53:06]

Was this test simply impossible to get as far with, given the ES2015 text?

[Dan Ehrenberg, 2016/03/10 20:00:42]

There's no such thing as "having no reject handler" in ES2015 promises. In the
debug-promises directory, there are many other tests which check various
rejection paths, such as mjsunit/es6/debug-promises/reject-with-throw-in-reject
.

-// caught by a custom promise, which has no reject handler.
-// We expect two Exception debug events:
-//  1) when the exception is thrown in the promise q.
-//  2) when calling the undefined custom reject closure in MyPromise throws.
-
-Debug = debug.Debug;
-
-var expected_events = 2;
-var log = [];
+// A non-callable reject function throws eagerly
 
 var p = new Promise(function(resolve, reject) {
   log.push("resolve");
   resolve();
 });
 
 function MyPromise(resolver) {
   var reject = undefined;
   var resolve = function() { };
-  log.push("construct");
   resolver(resolve, reject);
 };
 
 MyPromise.prototype = new Promise(function() {});
 MyPromise.__proto__ = Promise;
 p.constructor = MyPromise;
 
-var q = p.chain(
-  function() {
-    log.push("throw caught");
-    throw new Error("caught");  // event
-  });
-
-function listener(event, exec_state, event_data, data) {
-  try {
-    if (event == Debug.DebugEvent.Exception) {
-      expected_events--;
-      assertTrue(expected_events >= 0);
-      if (expected_events == 1) {
-        assertTrue(
-            exec_state.frame(0).sourceLineText().indexOf('// event') > 0);
-        assertEquals("caught", event_data.exception().message);
-      } else if (expected_events == 0) {
-        // All of the frames on the stack are from native Javascript.
-        assertEquals(0, exec_state.frameCount());
-        assertEquals("(var).reject is not a function",
-                     event_data.exception().message);
-      } else {
-        assertUnreachable();
-      }
-      assertSame(q, event_data.promise());
-    }
-  } catch (e) {
-    %AbortJS(e + "\n" + e.stack);
-  }
-}
-
-Debug.setBreakOnUncaughtException();
-Debug.setListener(listener);
-
-log.push("end main");
-
-function testDone(iteration) {
-  function checkResult() {
-    try {
-      assertTrue(iteration < 10);
-      if (expected_events === 0) {
-        assertEquals(["resolve", "construct", "end main", "throw caught"], log);
-      } else {
-        testDone(iteration + 1);
-      }
-    } catch (e) {
-      %AbortJS(e + "\n" + e.stack);
-    }
-  }
-
-  %EnqueueMicrotask(checkResult);
-}
-
-testDone(0);
+assertThrows(()=> p.then(function() { }), TypeError);