NewSubTest(name string) Test
	NewSubTestf(format string, a ...any) Test

	// WorkDir allocated for this test.
	WorkDir() string

	// CreateDirectoryOrFail creates a new sub directory with the given name in the workdir, or fails the test.
	CreateDirectoryOrFail(name string) string

	// CreateTmpDirectoryOrFail creates a new temporary directory with the given prefix in the workdir, or fails the test.