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_retrieve_header():
"""The header is retrieved as expected"""
stegs = Steganographer()
test_message = "12345".encode('utf-8')
test_data_len = len(test_message)
test_bits_used = 1
test_file_name = "test_retrieve_header.txt"
test_file_name_len = len(test_file_name)
test_data = bytes(b'\x01' * 1000)
test_header = stegs._generate_header(test_data_len, test_bits_used,
test_file_name)
hidden_data = stegs._hide_data(
test_data[:stegs._header.header_length * stegs._BYTELEN], test_header)
hidden_data += stegs._hide_data(
test_data[stegs._header.header_length * stegs._BYTELEN:], test_message)
header_retrieved = stegs._retrieve_header(hidden_data)
assert header_retrieved is True
assert stegs._header.data_len == test_data_len
assert stegs._header.bits_used == test_bits_used
assert stegs._header.file_name_len == test_file_name_len
assert stegs._header.file_name.decode('utf-8') == test_file_name
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_hide_data_partial():
"""Will work when given a bytes object that is too short to contain the full data to be hidden."""
stegs = Steganographer()
test_data = bytes(b'\x01' * stegs._BYTELEN * 3)
data_to_hide = bytes('ABC', 'utf-8')
stegs._header.data_len = len(data_to_hide)
solution_data = bytearray(stegs._BYTELEN * 3)
solution_data[1] = 1
solution_data[7] = 1
solution_data[9] = 1
solution_data[14] = 1
solution_data[17] = 1
solution_data[22] = 1
solution_data[23] = 1
# Testing when only half a byte is passed in for the data that contains the hidden text.
assert stegs._hide_data(test_data[:4], data_to_hide) == solution_data[:4]
def test_hide_data():
"""Will hide one bytes object inside another."""
stegs = Steganographer()
test_data = bytes(b'\x01' * stegs._BYTELEN * 4)
data_to_hide = bytes('ABC', 'utf-8')
stegs._header.data_len = len(data_to_hide)
solution_data = bytearray(stegs._BYTELEN * 4)
solution_data[1] = 1
solution_data[7] = 1
solution_data[9] = 1
solution_data[14] = 1
solution_data[17] = 1
solution_data[22] = 1
solution_data[23] = 1
solution_data[24:] = b'\x01' * stegs._BYTELEN
assert stegs._hide_data(test_data, data_to_hide) == solution_data