lib/web_ui/test/engine/hash_codes_test.dart

// Copyright 2013 The Flutter Authors. 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:test/bootstrap/browser.dart';
import 'package:test/test.dart';
import 'package:ui/ui.dart';

// The biggest integer value that can be represented in JavaScript is 1 << 53.
// However, the 1 << 53 expression cannot be used in JavaScript because that
// would apply the bitwise shift to a "number" (i.e. float64), which is
// meaningless. Instead, a decimal literal is used here.
const int _kBiggestExactJavaScriptInt = 9007199254740992;

void main() {
  internalBootstrapBrowserTest(() => testMain);
}

void testMain() {
  test('hashValues and hashList can hash lots of huge values effectively', () {
    final int hashValueFromArgs = hashValues(
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
    );

    // Hash the same values via a list
    final int hashValueFromList = hashList(<int>[
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
    ]);

    // Hash a slightly smaller number to verify that the hash code is different.
    final int slightlyDifferentHashValueFromArgs = hashValues(
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt,
      _kBiggestExactJavaScriptInt - 1,
    );

    final int slightlyDifferentHashValueFromList = hashList(<int>[
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt,
        _kBiggestExactJavaScriptInt - 1,
    ]);

    expect(hashValueFromArgs, equals(hashValueFromList));
    expect(slightlyDifferentHashValueFromArgs, equals(slightlyDifferentHashValueFromList));
    expect(hashValueFromArgs, isNot(equals(slightlyDifferentHashValueFromArgs)));
  });
}