Bump SDK constraints for pub (#158) Use a 2.12.0 lower bound since pub does not understand allowed experiments for earlier versions. Use a 3.0.0 upper bound to avoid a warning in pub and to give some flexibility in publishing for stable.
Support for specifying test expectations, such as for unit tests.
The matcher library provides a third-generation assertion mechanism, drawing inspiration from Hamcrest.
For more information, see Unit Testing with Dart.