Stub

MockeryPHP

A simple yet flexible PHP mock object framework for unit testing with a human-readable DSL.

Sinon.JSJavaScript

Standalone and test framework agnostic JavaScript test spies, stubs and mocks.

OHHTTPStubsObjective-C

A library for stubbing network requests in iOS/macOS/tvOS apps to test with fake data and simulate network conditions.

typeshedPython

A collection of external type annotations (stubs) for the Python standard library and third-party packages.

CuckooSwift

A boilerplate-free mocking framework for Swift with a Mockito-like DSL, using compile-time code generation.