TestWidgetsFlutterBinding.clock 变动
Summary
The TestWidgetsFlutterBinding.clock now comes from
package:clock and not package:quiver.
Context
The flutter_test package is removing its dependency on
the heavier weight quiver package in favor of a dependency
on two more targeted and lighter weight packages,
clock and fake_async.
This can affect user code which grabs the clock from a
TestWidgetsFlutterBinding and passes that to an API
that expects a Clock from package:quiver,
for example some code like this:
testWidgets('some test', (WidgetTester tester) {
someApiThatWantsAQuiverClock(tester.binding.clock);
});
Migration guide
The error you might see after this change looks something like this:
Error: The argument type 'Clock/*1*/' can't be assigned to the parameter type 'Clock/*2*/'.
- 'Clock/*1*/' is from 'package:clock/src/clock.dart' ('<pub-cache>/clock/lib/src/clock.dart').
- 'Clock/*2*/' is from 'package:quiver/time.dart' ('<pub-cache>/quiver/lib/time.dart').
Option #1: Create a package:quiver Clock from a package:clock Clock
The easiest migration is to create a package:quiver clock from the
package:clock clock, which can be done by passing the .now function
tearoff to the Clock constructor:
Code before migration:
testWidgets('some test', (WidgetTester tester) {
someApiThatWantsAQuiverClock(tester.binding.clock);
});
Code after migration:
testWidgets('some test', (WidgetTester tester) {
someApiThatWantsAQuiverClock(Clock(tester.binding.clock.now));
});
Option #2: Change the api to accept a package:clock Clock
If you own the api you are calling,
you may want to change it to accept a Clock
from package:clock.
This is a judgement call based on how many places are
calling this API with something other than a clock
retrieved from a TestWidgetsFlutterBinding.
If you go this route, your call sites that are passing
tester.binding.clock won’t need to be modified,
but other call sites will.
Option #3: Change the API to accept a DateTime function()
If you only use the Clock for its now function,
and you control the API, then you can also change it
to accept that function directly instead of a Clock.
This makes it easily callable with either type of Clock,
by passing a tearoff of the now method from either type of clock:
Calling code before migration:
testWidgets('some test', (WidgetTester tester) {
someApiThatWantsAQuiverClock(tester.binding.clock);
});
Calling code after migration:
testWidgets('some test', (WidgetTester tester) {
modifiedApiThatTakesANowFunction(tester.binding.clock.now);
});
Timeline
Landed in version: 1.18.0
In stable release: 1.20
References
API documentation:
Relevant PRs:
- PR 54125: remove flutter_test quiver dep, use fake_async and clock instead