test/stopwatch_test.dart

// Copyright 2018 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the 'License');
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an 'AS IS' BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import 'package:clock/clock.dart';

import 'package:test/test.dart';

import 'utils.dart';

void main() {
  test("returns the system frequency", () {
    expect(fixed(1990, 11, 8).stopwatch().frequency,
        equals(new Stopwatch().frequency));
  });

  group("before it starts", () {
    Stopwatch stopwatch;
    setUp(() {
      stopwatch = clock.stopwatch();
    });

    test("is not running", () => expect(stopwatch.isRunning, isFalse));

    test("stop() does nothing", () {
      stopwatch.stop();
      expect(stopwatch.isRunning, isFalse);
      expect(stopwatch.elapsed, equals(Duration.zero));
    });

    group("reports no elapsed", () {
      test("duration", () => expect(stopwatch.elapsed, equals(Duration.zero)));
      test("ticks", () => expect(stopwatch.elapsedTicks, isZero));
      test("microseconds", () => expect(stopwatch.elapsedMicroseconds, isZero));
      test("milliseconds", () => expect(stopwatch.elapsedMilliseconds, isZero));
    });
  });

  group("when 12345μs have elapsed", () {
    DateTime time;
    Clock clock;
    Stopwatch stopwatch;
    setUp(() {
      time = date(1990, 11, 8);
      clock = new Clock(() => time);
      stopwatch = clock.stopwatch()..start();
      time = clock.microsFromNow(12345);
    });

    group("and the stopwatch is active", () {
      test("is running", () {
        expect(stopwatch.isRunning, isTrue);
      });

      test("reports more elapsed time", () {
        time = clock.microsFromNow(54321);
        expect(stopwatch.elapsedMicroseconds, equals(66666));
      });

      test("start does nothing", () {
        stopwatch.start();
        expect(stopwatch.isRunning, isTrue);
        expect(stopwatch.elapsedMicroseconds, equals(12345));
      });

      group("reset()", () {
        setUp(() {
          stopwatch.reset();
        });

        test("sets the elapsed time to zero", () {
          expect(stopwatch.elapsed, equals(Duration.zero));
        });

        test("reports more elapsed time", () {
          time = clock.microsFromNow(54321);
          expect(stopwatch.elapsedMicroseconds, equals(54321));
        });
      });

      group("reports elapsed", () {
        test("duration", () {
          expect(stopwatch.elapsed, equals(new Duration(microseconds: 12345)));
        });

        test("ticks", () {
          expect(stopwatch.elapsedTicks,
              equals((new Stopwatch().frequency * 12345) ~/ 1000000));
        });

        test("microseconds", () {
          expect(stopwatch.elapsedMicroseconds, equals(12345));
        });

        test("milliseconds", () {
          expect(stopwatch.elapsedMilliseconds, equals(12));
        });
      });
    });

    group("and the stopwatch is inactive, reports that as", () {
      setUp(() {
        stopwatch.stop();
      });

      test("is not running", () {
        expect(stopwatch.isRunning, isFalse);
      });

      test("doesn't report more elapsed time", () {
        time = clock.microsFromNow(54321);
        expect(stopwatch.elapsedMicroseconds, equals(12345));
      });

      test("start starts reporting more elapsed time", () {
        stopwatch.start();
        expect(stopwatch.isRunning, isTrue);
        time = clock.microsFromNow(54321);
        expect(stopwatch.elapsedMicroseconds, equals(66666));
      });

      group("reset()", () {
        setUp(() {
          stopwatch.reset();
        });

        test("sets the elapsed time to zero", () {
          expect(stopwatch.elapsed, equals(Duration.zero));
        });

        test("doesn't report more elapsed time", () {
          time = clock.microsFromNow(54321);
          expect(stopwatch.elapsed, equals(Duration.zero));
        });
      });

      group("reports elapsed", () {
        test("duration", () {
          expect(stopwatch.elapsed, equals(new Duration(microseconds: 12345)));
        });

        test("ticks", () {
          expect(stopwatch.elapsedTicks,
              equals((new Stopwatch().frequency * 12345) ~/ 1000000));
        });

        test("microseconds", () {
          expect(stopwatch.elapsedMicroseconds, equals(12345));
        });

        test("milliseconds", () {
          expect(stopwatch.elapsedMilliseconds, equals(12));
        });
      });
    });
  });
}