Test Naming Conventions in Golang

I’m trying to unit test a Go package for the first time, and I have a couple of errors in the same file.

type FooErr int
type BarErr int

func (e *FooErr) Error () string {
    return "A Foo Error has occurred"
}

func (e *BarErr) Error () string {
    return "A Bar Error has occurred"
}

However, all naming conventions seem to look like this func TestXxx(*testing.T) (from the testing package documentation). This would mean my testing file would look like this:

func TestError (t *testing.T) { ... } // FooErr
func TestError (t *testing.T) { ... } // BarErr

Which is obviously two functions of the same signature. What is the recommended method for handling this?