mocktail library Null safety

A Dart mock library which simplifies mocking with null safety support and no manual mocks or code generation.


A captured method or property accessor -> a function that returns a value.
A stand-in for another object which cannot be used except for specifically overridden methods.
Extend or mixin this class to mark the implementation as a Mock.
Information about a stub call verification.
Result of when which enables methods to be stubbed via


Returns the list of argument lists which were captured within verifyInOrder.


untilCalled Future<Invocation> Function<T>(T _())
Returns a future Invocation that will complete upon the first occurrence of the given invocation.
verify → _Verify
Verify that a method on a mock object was called with the given arguments.
verifyInOrder List<VerificationResult> Function<T>(List<T Function()> recordedInvocations)
Verifies that a list of methods on a mock object have been called with the given arguments. For example:
verifyNever → _Verify
Verify that a method on a mock object was never called with the given arguments.
when When<T> Function<T>(T x())
Create a stub method response.


any<T>({String? named, Matcher? that}) → T
An argument matcher that matches any argument passed in.
captureAny<T>({String? named, Matcher? that}) → T
An argument matcher that captures any argument passed in.
clearInteractions(dynamic mock) → void
Clear the collected interactions with mock.
logInvocations(List<Mock> mocks) → void
Print all collected invocations of any mock methods of mocks.
registerFallbackValue(dynamic value) → void
Allows any and captureAny to be used on parameters of type value.
reset(dynamic mock) → void
Clear stubs of, and collected interactions with mock.
resetMocktailState() → void
Reset the state of Mocktail, typically for use between tests.
throwOnMissingStub(Mock mock, {void exceptionBuilder(Invocation)?}) → void
Opt-into Mock throwing NoSuchMethodError for unimplemented methods.
verifyNoMoreInteractions(dynamic mock) → void
Ensure no redundant invocations occur.
verifyZeroInteractions(dynamic mock) → void
Ensure interactions never happened on a mock.


Answer<T> = T Function(Invocation invocation)
Returns a value dependent on the details of an invocation.

Exceptions / Errors

An error which is thrown when no stub is found which matches the arguments of a real method call on a mock object.