wav scaffolding and tests

stegano/wav/__init__.py

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+#!/usr/bin/env python
+
+from .wav import hide, reveal
+
+__all__ = ["hide", "reveal"]

stegano/wav/wav.py

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+#!/usr/bin/env python
+# Stegano - Stéganô is a basic Python Steganography module.
+# Copyright (C) 2010-2024  Cédric Bonhomme - https://www.cedricbonhomme.org
+#
+# For more information : https://github.com/cedricbonhomme/Stegano
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>
+
+__author__ = "Cedric Bonhomme"
+__version__ = "$Revision: 0.2 $"
+__date__ = "$Date: 2010/10/01 $"
+__revision__ = "$Date: 2017/02/06 $"
+__license__ = "GPLv3"
+
+from typing import IO, Union
+
+import wave
+
+def hide(input_file: Union[str, IO[bytes]], message: str, output_file: Union[str, IO[bytes]]):
+    """
+    Hide a message (string) in a .wav audio file.
+
+    Use the lsb of each sample to hide the message string characters as ASCII values.
+    The first eight bits are used for message_length of the string.
+    """
+    message_length = len(message)
+    assert message_length != 0, "message message_length is zero"
+    # TODO messages in audio files could likely be much longer in most cases
+    assert message_length < 255, "message is too long"
+
+    output = wave.open(output_file, "wb")
+    with wave.open(input_file, "rb") as input:
+        pass
+        # TODO
+
+
+def reveal(input_file: Union[str, IO[bytes]]):
+    """
+    Find a message in an image.
+
+    Check the lsb of each sample for hidden message characters (ASCII values).
+    The first eight bits are used for message_length of the string.
+    """
+    message = ""
+    with wave.open(input_file, "rb") as input:
+        pass
+        # TODO
+    return message

tests/test_wav.py

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+#!/usr/bin/env python
+# Stegano - Stegano is a pure Python steganography module.
+# Copyright (C) 2010-2025 Cédric Bonhomme - https://www.cedricbonhomme.org
+#
+# For more information : https://github.com/cedricbonhomme/Stegano
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>
+
+__author__ = "Cedric Bonhomme"
+__version__ = "$Revision: 0.1 $"
+__date__ = "$Date: 2016/05/19 $"
+__license__ = "GPLv3"
+
+import os
+import unittest
+
+from stegano import wav
+
+
+class TestWav(unittest.TestCase):
+    def test_hide_empty_message(self):
+        """
+        Test hiding the empty string.
+        """
+        with self.assertRaises(AssertionError):
+            wav.hide("./tests/sample-files/free-software-song.wav", "", "./audio.wav")
+
+    def test_hide_and_reveal(self):
+        messages_to_hide = ["a", "foo", "Hello World!", ":Python:"]
+
+        for message in messages_to_hide:
+            wav.hide("./tests/sample-files/free-software-song.wav", message, "./audio.wav")
+            clear_message = wav.reveal("./audio.wav")
+
+            self.assertEqual(message, clear_message)
+
+    def test_with_too_long_message(self):
+        with open("./tests/sample-files/lorem_ipsum.txt") as f:
+            message = f.read()
+        with self.assertRaises(AssertionError):
+            wav.hide("./tests/sample-files/free-software-song.wav", message, "./audio.wav")
+
+    def tearDown(self):
+        try:
+            os.unlink("./audio.wav")
+        except Exception:
+            pass
+
+
+if __name__ == "__main__":
+    unittest.main()