def test_get__non_existing_element_no_default_provided__none_returned(faker):
sut = HashTable()
in_key = random.randrange(1000)
out_value = sut.get(in_key)
assert out_value is None
def test_add__resize__ok(faker, mocker):
initial_size = 10
keys = [
"".join(random.choices(string.ascii_uppercase + string.digits, k=5))
for _ in range(random.randrange(200, 1000))
]
log_mock = mocker.patch.object(hashtable_struct.log, "debug")
# check number of increase operations
fill_factor = 2 / 3
resize_ops = 0
while initial_size * pow(2, resize_ops) * fill_factor < len(keys):
resize_ops += 1
# Insert all elements
sut = HashTable(initial_size)
for k in keys:
sut.add(k, str(k))
# Validate all elements in HashTable
for k in keys:
val = sut[k]
assert val == str(k)
expected_calls = []
for i in range(1, resize_ops + 1):
expected_calls.append(
mock.call("HashTable is pretty filled. Resizing..."))
expected_calls.append(
mock.call(f"New HashTable size is: {initial_size * pow(2, i)}"))
assert log_mock.mock_calls == expected_calls
def test_add__collisioning_elements__ok(faker):
initial_size = 10
# Build random string whose hash could match in the hashtable
keys = [
"".join(random.choices(string.ascii_uppercase + string.digits, k=10))
for _ in range(10000)
]
group_keys_by_hash = itertools.groupby(
keys, key=lambda e: hash(e) % initial_size)
# Select the group of values with more collisions
max_group = max(((k, list(g)) for k, g in group_keys_by_hash),
key=lambda g: len(g[1]))
if len(max_group[1]) < 2:
pytest.skip("No duplicated hash found. Skipping...")
sut = HashTable(initial_size)
key1 = max_group[1][0]
key2 = max_group[1][1]
exp_val1 = str(key1)
exp_val2 = str(key2)
# Add two keys with expected same hash cell
sut.add(key1, exp_val1)
sut.add(key2, exp_val2)
out_key1 = sut.get(key1)
out_key2 = sut.get(key2)
assert key1 != key2
assert out_key1 == exp_val1
assert out_key2 == exp_val2
def test_remove__non_existing_element__key_error(faker):
sut = HashTable()
in_key = random.randrange(1000)
with pytest.raises(KeyError) as actual_error:
sut.remove(in_key)
assert str(actual_error.value) == str(in_key)
def test_contains__check_existing_element__true(faker):
sut = HashTable()
in_key = random.randrange(1000)
sut.add(in_key, None)
actual_out = in_key in sut
assert actual_out == True
def test_get__non_existing_element_default_provided__default_returned(faker, ):
sut = HashTable()
in_key = random.randrange(1000)
expected_out = faker.pystr()
actual_out = sut.get(in_key, default_value=expected_out)
assert actual_out is expected_out
def test_add__non_existing_element__inserted(faker):
sut = HashTable()
in_key = random.randrange(1000)
in_value = faker.pystr()
assert in_key not in sut
sut.add(in_key, in_value)
out_value = sut.get(in_key)
assert in_value == out_value
def test_contains__check_non_existing_element__false(faker):
sut = HashTable()
in_key = random.randrange(1000)
actual_out = in_key in sut
assert actual_out == False
def test_get__non_existing_element_brackets_syntax__key_error(faker):
sut = HashTable()
in_key = random.randrange(1000)
with pytest.raises(KeyError) as actual_error:
sut[in_key]
assert str(actual_error.value) == str(in_key)
def test_add_get__brackets_syntax__ok(faker):
sut = HashTable()
in_key = random.randrange(1000)
in_value = faker.pystr()
sut[in_key] = in_value
out_value = sut[in_key]
assert in_value == out_value
def test_remove__existing_element_del_syntax__ok(faker):
sut = HashTable()
in_key = random.randrange(1000)
sut[in_key] = None
assert in_key in sut
del sut[in_key]
actual_out = in_key in sut
assert actual_out == False
def test_add__existing_element__updated(faker):
sut = HashTable()
in_key = random.randrange(1000)
insert_value = faker.pystr()
sut.add(in_key, insert_value)
assert in_key in sut
update_value = faker.pystr()
sut.add(in_key, update_value)
out_value = sut.get(in_key)
assert update_value == out_value
def test_remove__existing_element__ok(faker):
sut = HashTable()
in_key = random.randrange(1000)
sut.add(in_key, None)
assert in_key in sut
sut.remove(in_key)
actual_out = in_key in sut
assert actual_out == False