def test_next_bit_length_returns_the_bits_needed_to_encode_the_next_symbol(
self):
generator = SymbolGenerator(1, 1)
self.assertEqual(1, generator.next_bit_length
) # the next symbol will be the initial value
self.assertEqual(Symbol("1"), next(generator))
self.assertEqual(2, generator.next_bit_length)
self.assertEqual(Symbol("10"), next(generator))
self.assertEqual(2, generator.next_bit_length)
self.assertEqual(Symbol("11"), next(generator))
self.assertEqual(3, generator.next_bit_length)
self.assertEqual(Symbol("100"), next(generator))
def test_encode_wikipedia_example(self):
uncompressed_input = "TOBEORNOTTOBEORTOBEORNOT"
encoded = self.encoder.encode(uncompressed_input)
expected_encoded_raw = (
"10100011110001000101011111001000111000111101010001"
"1011011101011111100100011110100000100010"
)
expected_encoded = Symbol(expected_encoded_raw)
original_encoding = Symbol.from_dict(self.alphabet, uncompressed_input)
self.assertLess(len(expected_encoded), len(original_encoding))
self.assertEqual(expected_encoded, encoded)
def test_decode_wikipedia_example(self):
encoded_raw = (
"10100011110001000101011111001000111000111101010001101101110"
"1011111100100011110100000100010")
encoded_input = Symbol(encoded_raw)
decoded = self.decoder.decode(encoded_input)
self.assertEqual("TOBEORNOTTOBEORTOBEORNOT", decoded)
def test_encode_empty_string(self):
uncompressed_input = ""
encoded = self.encoder.encode(uncompressed_input)
self.assertEqual(Symbol(), encoded)
def test_start_from_provided_number_of_bits_and_value(self):
generator = SymbolGenerator(0, 4)
self.assertEqual(Symbol("0000"), next(generator))
self.assertEqual(4, generator.current_bit_length)
def test_linear_progression_when_needs_1_bit_more(self):
generator = SymbolGenerator(7, 3)
self.assertEqual(3, generator.current_bit_length)
next(generator) # yields the initial value
self.assertEqual(Symbol("1000"), next(generator))
self.assertEqual(4, generator.current_bit_length)
def test_linear_progression(self):
generator = SymbolGenerator(4, 3)
next(generator)
next(generator)
next(generator)
self.assertEqual(Symbol("111"), next(generator))
def test_decode_empty_input(self):
encoded_input = Symbol()
decoded = self.decoder.decode(encoded_input)
self.assertEqual("", decoded)