Kevin Millikin
fa1d2c896d
Expect.equals (and Expect.listEquals) takes expected first and actual second. When these are flipped in tests, the failure message can be super hard to understand. Bug: Change-Id: I1d3c5a31365fa41ee7bcc7781474d76de9184cd5 Reviewed-on: https://dart-review.googlesource.com/23420 Reviewed-by: Jonas Termansen <sortie@google.com> Commit-Queue: Kevin Millikin <kmillikin@google.com>
58 lines
1.5 KiB
Dart
58 lines
1.5 KiB
Dart
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'package:expect/expect.dart';
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void testCallsToGenericFn() {
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T f<T>(T a, T b) => ((a as dynamic) + b) as T;
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var x = (f as dynamic)<int>(40, 2);
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Expect.equals(x, 42);
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var y = (f as dynamic)<String>('hi', '!');
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Expect.equals(y, 'hi!');
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var dd2d = (x, y) => x;
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dd2d = f; // implicit <dynamic>
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x = (dd2d as dynamic)(40, 2);
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Expect.equals(x, 42);
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y = (dd2d as dynamic)('hi', '!');
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Expect.equals(y, 'hi!');
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}
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void testGenericFnAsArg() {
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h<T>(a) => a as T;
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Object foo(f(Object a), Object a) => f(a);
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Expect.throws(() => foo(h as dynamic, 42));
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var int2int = (int x) => x;
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T bar<T>(x) => x as T;
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dynamic list = <Object>[1, 2, 3];
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Expect.throws(() => list.map(bar));
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int2int = bar;
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Expect.listEquals([1, 2, 3], list.map(int2int).toList());
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}
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typedef T2T = T Function<T>(T t);
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void testGenericFnAsGenericFnArg() {
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h<T>(a) => a as T;
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S foo<S>(T2T f, S a) => f<S>(a);
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Expect.equals(foo<int>(h, 42), 42);
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Expect.equals(foo<dynamic>(h, 42), 42);
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Expect.equals(foo<int>(h as dynamic, 42), 42);
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Expect.equals(foo<dynamic>(h as dynamic, 42), 42);
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}
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void testGenericFnTypeToString() {
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T f<T>(T a) => a;
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Expect.equals(f.runtimeType.toString(), "<T>(T) => T");
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}
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main() {
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testCallsToGenericFn();
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testGenericFnAsArg();
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testGenericFnAsGenericFnArg();
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testGenericFnTypeToString();
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}
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