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use_test_throws_matchers

Contents
Stable

Use throwsA matcher instead of fail().

Details

#

Use the throwsA matcher instead of try-catch with fail().

BAD:

dart
// sync code
try {
  someSyncFunctionThatThrows();
  fail('expected Error');
} on Error catch (error) {
  expect(error.message, contains('some message'));
}

// async code
try {
  await someAsyncFunctionThatThrows();
  fail('expected Error');
} on Error catch (error) {
  expect(error.message, contains('some message'));
}

GOOD:

dart
// sync code
expect(
  () => someSyncFunctionThatThrows(),
  throwsA(isA<Error>().having((Error error) => error.message, 'message', contains('some message'))),
);

// async code
await expectLater(
  () => someAsyncFunctionThatThrows(),
  throwsA(isA<Error>().having((Error error) => error.message, 'message', contains('some message'))),
);

Enable

#

To enable the use_test_throws_matchers rule, add use_test_throws_matchers under linter > rules in your analysis_options.yaml file:

analysis_options.yaml
yaml
linter:
  rules:
    - use_test_throws_matchers

If you're instead using the YAML map syntax to configure linter rules, add use_test_throws_matchers: true under linter > rules:

analysis_options.yaml
yaml
linter:
  rules:
    use_test_throws_matchers: true

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-03-07. View source or report an issue.