Test double
Also called Stand-in, Fake, Stub, Spy, Dummy
Anything that replaces a real part of your system during a test, like a stunt double. It lets you test without charging a real card or waiting on a real server.
Every double is a claim about how the real thing behaves. Nothing checks that claim unless you make something check it, and an agent writes the claim from what it assumes.
Say it to your agent
“Do not call the real Stripe API in tests. Write a FakeGateway in tests/fakes/ that keeps charges in an array, and pass it in. Use the fake for the outside service only, and keep our own code real.”