tests/lib/async/catch_errors13_test.dart

// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:async_helper/async_helper.dart';
import "package:expect/expect.dart";
import 'dart:async';
import 'catch_errors.dart';

main() {
  asyncStart();
  Completer done = new Completer();

  var events = [];
  // Work around bug that makes scheduleMicrotask use Timers. By invoking
  // `scheduleMicrotask` here we make sure that asynchronous non-timer events
  // are executed before any Timer events.
  scheduleMicrotask(() {});

  // Test that errors are caught by nested `catchErrors`. Also uses
  // `scheduleMicrotask` in the body of a Timer.
  bool outerTimerRan = false;
  int outerTimerCounterDelayCount = 0;
  catchErrors(() {
    events.add("catch error entry");
    catchErrors(() {
      events.add("catch error entry2");
      Timer.run(() {
        throw "timer error";
      });

      // We want this timer to run after the timer below. When the machine is
      // slow we saw that the timer below was scheduled more than 50ms after
      // this line. A duration of 50ms was therefore not enough to guarantee
      // that this timer runs before the timer below.
      // Instead of increasing the duration to a bigger amount we decided to
      // verify that the other timer already ran, and reschedule if not.
      // This way we could reduce the timeout (to 10ms now), while still
      // allowing for more time, in case the machine is slow.
      void runDelayed() {
        new Timer(const Duration(milliseconds: 10), () {
          if (outerTimerRan) {
            scheduleMicrotask(() {
              throw "scheduleMicrotask";
            });
            throw "delayed error";
          } else if (outerTimerCounterDelayCount < 100) {
            outerTimerCounterDelayCount++;
            runDelayed();
          }
        });
      }

      runDelayed();
    }).listen((x) {
      events.add(x);
      if (x == "scheduleMicrotask") {
        throw "inner done throw";
      }
    });
    events.add("after inner");
    Timer.run(() {
      outerTimerRan = true;
      throw "timer outer";
    });
    throw "inner throw";
  }).listen((x) {
    events.add(x);
    if (x == "inner done throw") done.complete(true);
  }, onDone: () {
    Expect.fail("Unexpected callback");
  });

  done.future.whenComplete(() {
    // Give callbacks time to run.
    Timer.run(() {
      Expect.listEquals([
        "catch error entry",
        "catch error entry2",
        "after inner",
        "main exit",
        "inner throw",
        "timer error",
        "timer outer",
        "delayed error",
        "scheduleMicrotask",
        "inner done throw"
      ], events);
      asyncEnd();
    });
  });
  events.add("main exit");
}