Dart's `expect` and Matchers: Writing Better Tests
Dart's `expect` and Matchers are a grammar for your tests, letting you define complex rules beyond simple equality. Use them to verify values, check for exceptions, and test async Futures/Streams.
Dart's `expect` and Matchers give your tests a rich vocabulary. Instead of just checking for equality, you can create complex, readable rules like `allOf([contains('foo'), isNot(startsWith('bar'))])`. They are essential for validating synchronous values, testing for specific exceptions with `throwsA`, and verifying the results of asynchronous Futures and Streams. The main footgun is testing a Future directly; always use the `completion()` matcher to wait for its result before validation.
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