def test_hide_reveal_string_inverse(string_to_hide):
"""Anything hidden by _hide_string is revealed by _reveal_string."""
clean_data = bytes(b'\x01' * 5000)
stegs = Steganographer()
stegs._header.data_len = len(string_to_hide.encode('utf-8'))
revealed_string = stegs._reveal_string(
stegs._hide_string(clean_data, string_to_hide))
assert revealed_string == string_to_hide
def test_exact_data_with_string_inverse():
"""The string entered is the string returned. The storing data is the exact length needed."""
test_string = "This is a test String"
stegs = Steganographer()
stegs._header.data_len = len(test_string)
blank_data = bytes(b'\x01' * len(test_string) * stegs._BYTELEN)
revealed_string = stegs._reveal_string(
stegs._hide_string(blank_data, test_string))
assert test_string == revealed_string
def test_short_data_with_string_inverse():
"""When the data is too small, by a full byte, everything that can be returned is returned."""
test_string = "This is a test String"
stegs = Steganographer()
stegs._header.data_len = len(test_string)
blank_data = bytes(b'\x01' *
(len(test_string) * stegs._BYTELEN - stegs._BYTELEN))
revealed_string = stegs._reveal_string(
stegs._hide_string(blank_data, test_string))
assert test_string[:-1] == revealed_string
def test_short_partial_data_string_inverse():
"""When the data is too small, by a half byte, everything that can be returned is returned."""
test_string = "This is a test String"
stegs = Steganographer()
stegs._header.data_len = len(test_string)
solution_string = test_string[:-1] + chr(
ord(test_string[-1]) >> stegs._BYTELEN // 2 << stegs._BYTELEN // 2)
blank_data = bytes(
b'\x01' * (len(test_string) * stegs._BYTELEN - stegs._BYTELEN // 2))
revealed_string = stegs._reveal_string(
stegs._hide_string(blank_data, test_string))
assert solution_string == revealed_string
def test_reveal_string():
"""Returns a string representation of the data that was hidden in the test_data."""
solution = 'ABC'
stegs = Steganographer()
stegs._header.data_len = len(solution)
test_data = bytearray(stegs._BYTELEN * 4)
test_data[1] = 1
test_data[7] = 1
test_data[9] = 1
test_data[14] = 1
test_data[17] = 1
test_data[22] = 1
test_data[23] = 1
assert stegs._reveal_string(test_data) == solution