func TestMyFunction(t *testing.T) { c := gocheck.C(t) // Test that myFunction throws an error c.ExpectFailure(myFunction()) } func myFunction() error { return errors.New("test error") }In this example, the `myFunction` function always throws an error. The `TestMyFunction` test case uses the ExpectFailure function to assert that the function indeed throws an error. The expect failure function is part of the gocheck package, which provides many other testing utilities for Go. It is a useful package for developers who are building complex applications that require thorough testing.