test_binary_heap.py

# -*- coding: utf-8 -*-

import pytest
from binary_heap import BinaryHeap as B_heap

TEST_ARRAY = [123, 3, 32, 646, 7, 235]
TEST_ARRAY_2 = [15, 8, 14, 7, 6, 12]


@pytest.fixture(scope="function")
def test_heap():
    test_heap = B_heap()
    test_heap.push(7)
    test_heap.push(8)
    test_heap.push(9)
    test_heap.push(3)

    return test_heap


def test_constructor():
    test = B_heap()
    assert test._list == []


def test_constructor_with_iterable():
    test = B_heap(TEST_ARRAY)
    assert test._list == [646, 123, 235, 3, 7, 32]


def test_push_value_is_inserted():
    test_heap = B_heap()
    test_heap.push(100)

    assert test_heap._list[0] == 100


def test_push_correctly_sorts(test_heap):
    assert test_heap._list == [9, 7, 8, 3]


def test_pop_empty():
    test_heap = B_heap()

    with pytest.raises(IndexError) as error:
        test_heap.pop()
    assert 'The heap is empty' in str(error.value)


def test_pop_maintains_heap():
    test_heap = B_heap(TEST_ARRAY_2)

    assert test_heap.pop() == 15
    assert test_heap._list == [14, 8, 12, 7, 6]


def test_pop_maintains_heap_2():
    test_heap = B_heap(TEST_ARRAY)

    assert test_heap.pop() == 646
    assert test_heap._list == [235, 123, 32, 3, 7]