LibTest/async/Future/catchError_A03_t05.dart

/*
 * Copyright (c) 2011, 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.
 */
/**
 * @assertion abstract Future catchError(Function onError, {bool test(Object error)})
 * When this completes with an error, test is called with the error's value.
 * If the invocation returns true, onError is called with the error.
 * The result of onError is handled exactly the same as for then's onError.
 * If test returns false, the exception is not handled by onError, but is thrown unmodified,
 * thus forwarding it to f.
 * If test is omitted, it defaults to a function that always returns true.
 * @description Checks that it is a runtime error if onError callback has more
 * than two parameters.
 * @author ilya
 */
import "dart:async";
import "../../../Utils/async_utils.dart";
import "../../../Utils/dynamic_check.dart";
import "../../../Utils/expect.dart";

f() {
  if (isCheckedMode()) {
    // in checked mode, registering incompatible callback is synchronious error,
    // future ends up with no error handler that will lead to async exception
    // with error object equal to 1.
    Expect.throws(() => new Future.error(1).catchError((x,y,z){}));
  } else {
    // in production mode, callback is registered, and will throw
    // asynchroniously upon execution.
    new Future.error(1).catchError((x,y,z){});
  }
}

main() {
  asyncStart();
  runZoned(f, onError: (e) {
    if (isCheckedMode()) {
      Expect.equals(1, e);
    } else {
      Expect.notEquals(1, e);
    }
    asyncEnd();
  });
}