def METHOD_NAME(self):
    times = numpy.array([
        [5.4, 7.1, 6.0, 5.4, 4.2],
        [6.4, 4.3, 8.9, 9.6, 3.8],
    ]) * 1e-6
    perf = _time._PerfCaseResult('test_name_xxx', times, (0,))
    expected = (
        'test_name_xxx       :'
        '    CPU:     5.620 us   +/-  0.943 '
        '(min:     4.200 / max:     7.100) us'
    )
    assert perf.to_str() == expected
    # Checks if the result does not change.
    assert perf.to_str() == expected