Update to latest test_* deps (#148) Add `test_api` and `test_core` to `dev_dependencies` in addition to `dependency_overrides`. This prevents a warning on publish about overriding non-dev dependencies. Use `any` constraints` for the `dev_dependencies` since they are already constrained correctly by `dependency_overrides`. Bump min SDK in pubspec and on Travis to match the latest `test`.
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.