def test_empty_sample_is_error():
rnd = Random(0)
sampler = Sampler()
with pytest.raises(IndexError):
sampler.sample(rnd)
sampler[1] = 1
sampler[1] = 0
with pytest.raises(IndexError):
sampler.sample(rnd)
def test_samples_only_non_zero_while_updating(weights, rnd):
sampler = Sampler()
model = {}
for k, v in weights:
model[k] = v
sampler[k] = v
if v > 0:
assert sampler[k] == model[k]
else:
assert k not in sampler
if sum(model.values()) > 0:
s = sampler.sample(rnd)
assert model[s] > 0
def test_can_delete_an_item(rnd, data, weights):
keys = sorted(weights)
sampler = Sampler(weights)
key = data.draw(st.sampled_from(keys))
del sampler[key]
assert sampler.sample(rnd) != key
def test_sample_from_single(rnd):
sampler = Sampler()
sampler[0] = 1
assert sampler.sample(rnd) == 0
def test_samples_only_non_zero(weights, rnd):
assume(sum(weights.values()) > 0)
sampler = Sampler(weights)
assert weights[sampler.sample(rnd)] > 0