def test_get_codes(self, d):
"""the sum of len(code) * freq_dict[code] is optimal, so it
must be invariant under permutation of the dictionary"""
# NB: this also tests huffman_tree indirectly
t = huffman_tree(d)
c1 = get_codes(t)
d2 = list(d.items())
shuffle(d2)
d2 = dict(d2)
t2 = huffman_tree(d2)
c2 = get_codes(t2)
self.assertEqual(sum([d[k] * len(c1[k]) for k in d]),
sum([d2[k] * len(c2[k]) for k in d2]))
def test_round_trip(self, b):
"""test inverting generate_compressed and generate_uncompressed"""
orig_text = b
freq = make_freq_dict(orig_text)
assume(len(freq) > 1)
tree = huffman_tree(freq)
codes = get_codes(tree)
compressed = generate_compressed(orig_text, codes)
uncompressed = generate_uncompressed(tree, compressed, len(orig_text))
assert orig_text == uncompressed
def test_round_trip(self, b):
"""test inverting generate_compressed and generate_uncompressed"""
orig_text = b
freq = make_freq_dict(orig_text)
assume(len(freq) > 1)
tree = huffman_tree(freq)
codes = get_codes(tree)
compressed = generate_compressed(orig_text, codes)
uncompressed = generate_uncompressed(tree, compressed, len(orig_text))
assert orig_text == uncompressed #, '\n'.join([str(list(orig_text)), str(codes), byte_to_bits(compressed[0]), str(list(uncompressed))])
def test_generate_compressed(self, b):
"""generate_compressed should return a bytes
object that is no longer than the input bytes, and
the size of the compressed object should be
invariant under permuting the input"""
# NB: this also indirectly tests make_freq_dict, huffman_tree,
# and get_codes
d = make_freq_dict(b)
t = huffman_tree(d)
c = get_codes(t)
compressed = generate_compressed(b, c)
self.assertTrue(isinstance(compressed, bytes))
self.assertTrue(len(compressed) <= len(b))
l = list(b)
shuffle(l)
b = bytes(l)
d = make_freq_dict(b)
t = huffman_tree(d)
c = get_codes(t)
compressed2 = generate_compressed(b, c)
self.assertEqual(len(compressed2), len(compressed))
""" Sorted() by key test
l = [[2, 3], [6, 7], [3, 34], [24, 64], [1, 43]]
l = sorted(l, key=getkey)
print(l)
"""
""" Test using multiple arguements in for loop
d = make_freq_dict(bytes([65, 66, 67, 66]))
for k, v in d.items():
print(k, 'corresponds to', v)
"""
# Testing get_codes()
freq = {2: 6, 3: 4, 4: 13, 5: 17}
t = huffman_tree(freq)
d = get_codes(t)
print(t)
print(d)
freqs = {'a': 2}
d = HuffmanNode()
print(d)
print(get_codes(d))
print(bytes([65, 66, 67, 66]))
left = HuffmanNode(None, HuffmanNode(3), HuffmanNode(2))
right = HuffmanNode(None, HuffmanNode(9), HuffmanNode(10))
tree = HuffmanNode(None, left, right)
number_nodes(tree)
