def METHOD_NAME(self):
    self.dut._parse_file = mock.MagicMock()
    self.dut._add_to_filetree = mock.MagicMock()
    n = len(self.dut.get_all_datafiles())
    fn = list(self.dut._file_cache.keys())[0]
    del self.dut._file_cache[fn]
    self.dut.setup()
    assert self.dut._parse_file.call_count == 1
    assert self.dut._add_to_filetree.call_count == n