Test Double
In plain terms
A general term for any stand-in used in testing.
Going deeper
A test double replaces a real component during tests; it's the umbrella term covering stubs, mocks, spies, fakes, and dummies. Each type serves a different purpose.
Under the hood
Choosing the right double (state vs. interaction verification) keeps tests focused and robust.
Examples
Mocks, stubs, spies, fakes, dummies, isolating units under test.
Think of it like...
Like a stunt double standing in for the real actor during risky scenes.