def test_exact_data_with_data_inverse():
"""The data entered is the data returned. The storing data is the exact length needed."""
test_string = "This is a test String"
test_data = bytes(test_string, 'utf-8')
stegs = Steganographer()
stegs._header.data_len = len(test_string)
blank_data = bytes(b'\x01' * len(test_string) * stegs._BYTELEN)
revealed_data = stegs._reveal_data(stegs._hide_data(blank_data, test_data))
assert test_data == revealed_data
def test_hide_reveal_data_inverse(string_to_hide):
"""Anything hidden by _hide_data is revealed by _reveal_data."""
clean_data = bytes(b'\x01' * 5000)
data_to_hide = bytes(string_to_hide, 'utf-8')
stegs = Steganographer()
stegs._header.data_len = len(string_to_hide.encode('utf-8'))
revealed_data = stegs._reveal_data(
stegs._hide_data(clean_data, data_to_hide))
assert revealed_data == data_to_hide
def test_short_data_with_data_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"
test_data = bytes(test_string, 'utf-8')
stegs = Steganographer()
stegs._header.data_len = len(test_string)
blank_data = bytes(b'\x01' *
(len(test_string) * stegs._BYTELEN - stegs._BYTELEN))
revealed_data = stegs._reveal_data(stegs._hide_data(blank_data, test_data))
assert test_data[:-1] == revealed_data
def test_short_partial_data_w_data_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"
test_data = bytes(test_string, 'utf-8')
solution_data = bytearray(test_data)
stegs = Steganographer()
stegs._header.data_len = len(test_string)
solution_data[
-1] = solution_data[-1] >> stegs._BYTELEN // 2 << stegs._BYTELEN // 2
blank_data = bytes(
b'\x01' * (len(test_string) * stegs._BYTELEN - stegs._BYTELEN // 2))
revealed_data = stegs._reveal_data(stegs._hide_data(blank_data, test_data))
assert solution_data == revealed_data
def test_reveal_data():
"""Will return the correct data that is hidden inside the test_data."""
solution_data = bytes('ABC', 'utf-8')
stegs = Steganographer()
stegs._header.data_len = len(solution_data)
test_data = bytearray(stegs._BYTELEN * 3)
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_data(test_data) == solution_data
def test_reveal_data_partial():
"""
Will return as much data as possible.
When the container bytes object passed in is too small for all the data to be hidden.
"""
stegs = Steganographer()
solution_data = bytes('AB@', 'utf-8')
test_data = bytearray(
stegs._BYTELEN * 3
) # Will contain 'ABC' but will be truncated when passed to _reveal_data
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
stegs._data_len = len('ABC')
assert stegs._reveal_data(test_data[:-stegs._BYTELEN //
2]) == solution_data
