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_zero_weights_are_absent():
sampler = Sampler()
sampler[1] = 2
assert sampler[1] == 2
sampler[1] = 0
with pytest.raises(KeyError):
sampler[1]
def test_non_empty_sampler_is_truthy():
sampler = Sampler()
assert not sampler
sampler[0] = 1
assert sampler
del sampler[0]
assert not sampler
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_skips_zero_weights():
sampler = Sampler({1: 1, 2: 0, 3: 1})
assert sorted(sampler) == [1, 3]
def test_iterates_as_dict(weights):
sampler = Sampler(weights)
assert sorted(sampler) == sorted(weights)
assert sorted(sampler.items()) == sorted(weights.items())
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
def test_items_not_set_are_not_in_sampler():
sampler = Sampler()
assert 3 not in sampler