def test_calc_mean4(self):
    """ calc_mean case4: datalist format is incorrect. """
    filepath = 'resources/test_train/image-list4.txt'
    mean = dataset.calc_mean(filepath)
 def test_calc_mean2(self):
    """ calc_mean case2: 2 dataset """
    filepath = 'resources/test_train/image-list2.txt'
    mean = dataset.calc_mean(filepath)
    assert not mean is None
 def test_calc_mean3(self):
    """ calc_mean case3: datalist has an empty line. """
    filepath = 'resources/test_train/image-list3.txt'
    mean = dataset.calc_mean(filepath)
    assert not mean is None
 def test_calc_mean1(self):
    """ calc_mean case1: empty dataset """
    filepath = 'resources/test_train/image-list1.txt'
    mean = dataset.calc_mean(filepath)
    assert mean is None