clock

The clock package provides testable replacements for the system clock APIs (new DateTime.now() and new Stopwatch()).

##Usage

Access now and getStopwatch() instead of new DateTime.now() and new Stopwatch(). You may want to import with a prefix:

import'package:clock/clock.dart'as clock;
intget currentYear => clock.now.year;
DurationtimeAction(action()) {
var stopwatch = clock.getStopwatch()..start();
action();
return stopwatch.elapsed;
}

Then use withClock(new Clock(...), () { /* test code */ }); to make your tests deterministic:

import'package:clock/clock.dart';
import'package:unittest/unittest.dart';
import'time_utils.dart'; // What we're testing.main() {
group('time utils', () {
test('currentYear should return the current year', () {
withClock(newClock(initialTime:newDateTime(2014, 3, 6)), () {
expect(currentYear, 2014);
});
});
test('timeAction should time the action', () {
var elapsed =Duration.ZERO;
withClock(newClock(elapsed: () => elapsed), () {
expect(timeAction(() {
elapsed +=constDuration(seconds:5);
}), constDuration(seconds:5));
});
});
});
}