[esnext] prototype runtime implementation for async functions

test/mjsunit/mjsunit.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 36 matching lines @@
 // values.
 // For known primitive values, please use assertEquals.
 var assertSame;
 
 // Expected and found values are identical primitive values or functions
 // or similarly structured objects (checking internal properties
 // of, e.g., Number and Date objects, the elements of arrays
 // and the properties of non-Array objects).
 var assertEquals;
 
+var assertEqualsAsync;
 
 // The difference between expected and found value is within certain tolerance.
 var assertEqualsDelta;
 
 // The found object is an Array with the same length and elements
 // as the expected object. The expected object doesn't need to be an Array,
 // as long as it's "array-ish".
 var assertArrayEquals;
 
 // The found object must have the same enumerable properties as the
@@ skipping 19 matching lines @@
 // Checks that the found value is *not* null.
 var assertNotNull;
 
 // Assert that the passed function or eval code throws an exception.
 // The optional second argument is an exception constructor that the
 // thrown exception is checked against with "instanceof".
 // The optional third argument is a message type string that is compared
 // to the type property on the thrown exception.
 var assertThrows;
 
+var assertThrowsAsync;
+
 // Assert that the passed function throws an exception.
 // The exception is checked against the second argument using assertEquals.
 var assertThrowsEquals;
 
 // Assert that the passed function or eval code does not throw an exception.
 var assertDoesNotThrow;
 
 // Asserts that the found value is an instance of the constructor passed
 // as the second argument.
 var assertInstanceof;
@@ skipping 170 matching lines @@
   };
 
 
   assertEquals = function assertEquals(expected, found, name_opt) {
     if (!deepEquals(found, expected)) {
       fail(PrettyPrint(expected), found, name_opt);
     }
   };
 
 
+  assertEqualsAsync = function assertEqualsAsync(expected, run, msg) {
+    var actual;
+    var hadValue = false;
+    var hadError = false;
+    var promise = run();
+
+    if (typeof promise !== "object" || typeof promise.then !== "function") {
+      throw new MjsUnitAssertionError(
+          "Expected " + run.toString() +
+          " to return a Promise, but it returned " + PrettyPrint(promise));
+    }
+
+    promise.then(function(value) { hadValue = true; actual = value; },
+                 function(error) { hadError = true; actual = error; });
+
+    assertFalse(hadValue || hadError);
+
+    flushMicrotasks();
+
+    if (hadError) throw actual;
+
+    assertTrue(
+        hadValue, "Expected '" + run.toString() + "' to produce a value");
+
+    assertEquals(expected, actual, msg);
+  };
+
   assertEqualsDelta =
       function assertEqualsDelta(expected, found, delta, name_opt) {
     assertTrue(Math.abs(expected - found) <= delta, name_opt);
   };
 
 
   assertArrayEquals = function assertArrayEquals(expected, found, name_opt) {
     var start = "";
     if (name_opt) {
       start = name_opt + " - ";
@@ skipping 66 matching lines @@
       }
       if (arguments.length >= 3) {
         assertEquals(e.type, cause_opt);
       }
       // Success.
       return;
     }
     throw new MjsUnitAssertionError("Did not throw exception");
   };
 
+  assertThrowsAsync = function assertThrowsAsync(run, errorType, message) {
+    var actual;
+    var hadValue = false;
+    var hadError = false;
+    var promise = run();
+
+    if (typeof promise !== "object" || typeof promise.then !== "function") {
+      throw new MjsUnitAssertionError(
+          "Expected " + run.toString() +
+          " to return a Promise, but it returned " + PrettyPrint(promise));
+    }
+
+    promise.then(function(value) { hadValue = true; actual = value; },
+                 function(error) { hadError = true; actual = error; });
+
+    assertFalse(hadValue || hadError);
+
+    flushMicrotasks();
+
+    if (!hadError) {
+      throw new MjsUnitAssertionError(
+          "Expected " + run + "() to throw " + errorType.name +
+          ", but did not throw.");
+    }
+    if (!(actual instanceof errorType))
+      throw new MjsUnitAssertionError(
+          "Expected " + run + "() to throw " + errorType.name +
+          ", but threw '" + actual + "'");
+    if (message !== void 0 && actual.message !== message)
+      throw new MjsUnitAssertionError(
+          "Expected " + run + "() to throw '" + message + "', but threw '" +
+          actual.message + "'");
+  };
+
 
   assertThrowsEquals = function assertThrowsEquals(fun, val) {
     try {
       fun();
     } catch(e) {
       assertEquals(val, e);
       return;
     }
     throw new MjsUnitAssertionError("Did not throw exception");
   };
@@ skipping 52 matching lines @@
     if (sync_opt === undefined) sync_opt = "";
     assertTrue(OptimizationStatus(fun, sync_opt) !== 1, name_opt);
   }
 
   assertOptimized = function assertOptimized(fun, sync_opt, name_opt) {
     if (sync_opt === undefined) sync_opt = "";
     assertTrue(OptimizationStatus(fun, sync_opt) !== 2, name_opt);
   }
 
 })();