def test_encoder_exception(self):
encoder = HuffmanEncoder("There can be only one.")
encoder.build_frequency_dictionary()
encoder.build_priority_queue()
encoder.build_tree()
encoder.build_encode_dictionary_with_tree()
with self.assertRaises(
KeyError,
msg=
"Encoder should raise a KeyError when encountering a letter not in the frequency dictionary."
):
encoder.encode_message("Two to tango.")
def test_1_encode(self):
print("-------------------------------------\nTesting encode.")
encoder = HuffmanEncoder(
"I'm here to kick butt and chew bubblegum. And I'm all out of bubblegum."
)
encoder.build_frequency_dictionary()
encoder.build_priority_queue()
encoder.build_tree()
encoder.build_encode_dictionary_with_tree()
gibberish = encoder.encode_message(
"I'm here to kick butt and chew bubblegum. And I'm all out of bubblegum."
)
expected = [
0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1,
1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0,
0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1,
1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0,
1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1,
0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1,
1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0,
0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1,
1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0,
1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 0,
0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1,
1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1,
0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0,
1, 0, 1, 1, 1, 0, 1, 0, 0, 1
]
self.assertEqual(gibberish, expected, "Encoded text did not match.")
def test_3_short_encode_decode(self):
print(
"-----------------------------------\nTesting short encode decode")
douglas_adams = (
"There is an art to flying, or rather a knack. The knack lies in learning how to throw yourself at the ground and miss."
)
encoder = HuffmanEncoder(douglas_adams)
encoder.do_setup()
encoded_flying_quote = encoder.encode_message(douglas_adams)
decoded_flying_quote = encoder.decode_message(encoded_flying_quote)
self.assertEqual(douglas_adams, decoded_flying_quote)
print(decoded_flying_quote)
print(
f"Original size in ASCII: {8 * len(douglas_adams)} bits ({len(douglas_adams)} bytes)"
)
print(
f"encoded length: {len(encoded_flying_quote)} bits ({int(len(encoded_flying_quote) / 8+0.9)} bytes)"
)
print(
f"compression ratio: {len(encoded_flying_quote) / len(douglas_adams) / 8 * 100:3.2f}%"
)
def test_4_long_encode_decode(self):
print(
"-----------------------------------\nTesting long encode decode")
gettysberg = ("Four score and seven years ago our fathers brought forth on this continent, a new nation, " \
"conceived in Liberty, and dedicated to the proposition that all men are created equal.\n" \
"Now we are engaged in a great civil war, testing whether that nation, or any nation so " \
"conceived and so dedicated, can long endure. We are met on a great battle-field of that " \
"war. We have come to dedicate a portion of that field, as a final resting place for those " \
"who here gave their lives that that nation might live. It is altogether fitting and proper " \
"that we should do this.\n" \
"But, in a larger sense, we can not dedicate -- we can not consecrate -- we can not hallow " \
"-- this ground. The brave men, living and dead, who struggled here, have consecrated it, " \
"far above our poor power to add or detract. The world will little note, nor long remember " \
"what we say here, but it can never forget what they did here. It is for us the living, " \
"rather, to be dedicated here to the unfinished work which they who fought here have thus " \
"far so nobly advanced. It is rather for us to be here dedicated to the great task remaining " \
"before us -- that from these honored dead we take increased devotion to that cause for which " \
"they gave the last full measure of devotion -- that we here highly resolve that these dead " \
"shall not have died in vain -- that this nation, under God, shall have a new birth of freedom " \
"-- and that government of the people, by the people, for the people, shall not perish from the " \
"earth.\nAbraham Lincoln\nNovember 19, 1863")
encoder = HuffmanEncoder(gettysberg)
encoder.do_setup()
encoded_getty = encoder.encode_message(gettysberg)
reset_getty = encoder.decode_message(encoded_getty)
self.assertEqual(gettysberg, reset_getty)
print(reset_getty)
print(
f"Original size in ASCII: {8 * len(gettysberg)} bits ({len(gettysberg)} bytes)"
)
print(
f"encoded length: {len(encoded_getty)} bits ({int(len(encoded_getty)/8+0.9)} bytes)"
)
print(
f"compression ratio: {(len(encoded_getty) / len(gettysberg) / 8 * 100):3.2f}%"
)