def test_flip_matrix(self, input, expected_output):
"""Test taking the absolute values of eigenvalues of a matrix."""
assert np.allclose(kern.flip_matrix(input), expected_output)
def test_do_nothing_on_non_negative(self, input):
"""Test thresholding, displacing and flipping matrix to do nothing on PSD matrices."""
assert np.allclose(kern.threshold_matrix(input), input)
assert np.allclose(kern.displace_matrix(input), input)
assert np.allclose(kern.flip_matrix(input), input)