def test_maxheap(self):
"""verifies that heap.build_maxheap() returns an array that satisfies
the max_heap property."""
h = Heap(self.unsorted_array)
h.build_max_heap()
list_1 = h.get_array()
self.assertTrue(self.is_maxheap(list_1))
def test_sort_does_not_work(self):
"""makes sure that heap does not return a sorted array before
sort is called. sounds stupid but needs to be done lol."""
h = Heap(self.unsorted_array)
h.build_max_heap()
list_1 = h.get_array() # should probably change this method name. bad name.
list_2 = sorted(self.unsorted_array)
self.assertNotEqual(list_1, list_2)
def test_heapsort_correctness_after_insertion(self):
"""tests to see if heap sort works properly after element insertion."""
h = Heap(self.unsorted_array)
h.build_max_heap()
h.insert(5)
h.insert(10)
self.unsorted_array.append(5)
self.unsorted_array.append(10)
h.heap_sort()
sorted_array = sorted(self.unsorted_array)
list_1 = h.get_array()
self.assertEqual(sorted_array, list_1)
def test_sort_correctness(self):
"""tests to see whether or not Heap sorts correctly by sorting
a list using heap sort and comparing it to a sort using python's
standard library sort."""
# initialize heap with this array
h = Heap(self.unsorted_array)
# build the heap using max heapify
h.build_max_heap()
# sort the array using heap sort
h.heap_sort()
list1 = h.get_array()
list2 = sorted(self.unsorted_array)
self.assertEqual(list1, list2)
def test_heap_correctness_after_insertion(self):
"""checks to see whether or not heap constraints are satisified after insertion.
Heap Property: each node should be greater than or equal to its parent
The parent of element i in a binary heap stored in an array element
is (i - 1) // 2.
found on stackoverflow:
https://stackoverflow.com/questions/16414671/\
determining-if-a-list-of-numbers-is-in-heap-order-python-3-2
"""
# NOTE:
# is_heap and heapq.heapify(x) BOTH implement min heaps and
# Heap() uses max heap. we need to invert the values so that
# our max-heap turns in to a min-heap to verify correctness.
# the other alternative is to actually write a max-heap checker
# or actually implement min-heap.
h = Heap(self.unsorted_array)
h.build_max_heap()
for i in range(9):
h.insert(i)
list_1 = h.get_array()
self.assertTrue(self.is_maxheap(list_1))
