def test_when_run_where_then_return_correct_values(self):
enumerable = Enumerable(generate)
where_enumerable = enumerable.where(lambda x: x > 2)
self.assertIsInstance(where_enumerable, Enumerable)
values = where_enumerable.to_list()
self.assertSequenceEqual(values, [3, 4, 5, 6, 7])
def test_when_create_several_enumerables_from_same_enumerable_then_return_correct_values(
self):
enumerable_1 = Enumerable(generate).where(lambda x: x > 0)
enumerable_2 = enumerable_1.where(lambda x: x > 4)
enumerable_3 = enumerable_1.where(lambda x: x < 4)
self.assertSequenceEqual(enumerable_3.to_list(), [1, 2, 3])
self.assertSequenceEqual(enumerable_2.to_list(), [5, 6, 7])
def test_when_run_several_where_in_sequence_then_run_interleaved(self):
sequence = []
def less_than_5(x):
w = x < 5
sequence.append(5)
return w
def greater_than_2(x):
w = x > 2
sequence.append(2)
return w
enumerable = Enumerable(generate)
values = enumerable.where(greater_than_2).where(less_than_5).to_list()
self.assertSequenceEqual(values, [3, 4])
self.assertSequenceEqual(sequence,
[2, 2, 2, 2, 5, 2, 5, 2, 5, 2, 5, 2, 5])