def test_with_tolerable_noise(self):
def add_noise(x, step):
'''
Add tolerable noise. Return noisy signal
Arguments
x -- amplitude of signal
step -- quantization step
'''
noise = random.random() * step / 4
return x + random.choice([-1, 1]) * noise
step = 6
d0 = random.uniform(-3, 3)
x = random.random() * 100
quantizer = UniformQuantizer(step)
emb = BinaryDM(quantizer, d0)
# embed a zero
sm = emb.embed(x, 0)
y = add_noise(sm, step)
self.assertEqual(emb.extract(y), 0)
# embed a one
sm = emb.embed(x, 1)
y = add_noise(sm, step)
self.assertEqual(emb.extract(y), 1)
def test_without_noise(self):
step = 12
d0 = random.uniform(-6, 6)
x = random.random() * 100
quantizer = UniformQuantizer(step)
emb = BinaryDM(quantizer, d0)
# embed a zero
self.assertEqual(emb.extract(emb.embed(x, 0)), 0)
# embed a one
self.assertEqual(emb.extract(emb.embed(x, 1)), 1)
def test_zero_embedded(self):
quantizer = MagicMock()
emb = BinaryDM(quantizer, d0=5)
# emb.embed(x, 0) => 12
# emb.embed(x, 1) => 5
emb.embed = Mock(side_effect=[12, 5])
self.assertEqual(emb.extract(10), 0)
self.assertListEqual(emb.embed.call_args_list,
[call(10, 0), call(10, 1)])
# Equal distance
emb.embed = Mock(side_effect=[2, 2])
self.assertEqual(emb.extract(10), 0)
self.assertListEqual(emb.embed.call_args_list,
[call(10, 0), call(10, 1)])