def test_get_error():
lay = Layer(1, 1)
lay.output = np.zeros((1, 1))
target = np.ones((1, 1))
expected_error = 0.5
actual_error = lay.get_error(target)
assert expected_error == actual_error
target = target * 0
expected_error = 0
actual_error = lay.get_error(target)
assert expected_error == actual_error
lay = Layer(2, 2)
lay.output = np.zeros((2, 2))
target = np.array([
[1, 2], # batch 1
[3, 4] # batch 2
])
expected_error = 0.5 * (1 * 1 + 2 * 2 + 3 * 3 + 4 * 4)
actual_error = lay.get_error(target)
assert expected_error == actual_error
