Make an assertion, error will be thrown if expr does not have truthy value.

Make an assertion that actual and expected are equal, deeply. If not deeply equal, then throw.

Executes a function which returns a promise, expecting it to reject.

Asserts that a spy is called as expected.

Executes a function, expecting it to throw. If it does not, then it throws.

Wraps a function or instance method with a Spy.