Add tests to morse_code.py (#5337)

* Add tests to morse_code.py

@dhruvmanila @poyea Your reviews, please.

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

ciphers/morse_code.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+
+"""
+Python program to translate to and from Morse code.
+
+https://en.wikipedia.org/wiki/Morse_code
+"""
+
+# fmt: off
+MORSE_CODE_DICT = {
+    "A": ".-", "B": "-...", "C": "-.-.", "D": "-..", "E": ".", "F": "..-.", "G": "--.",
+    "H": "....", "I": "..", "J": ".---", "K": "-.-", "L": ".-..", "M": "--", "N": "-.",
+    "O": "---", "P": ".--.", "Q": "--.-", "R": ".-.", "S": "...", "T": "-", "U": "..-",
+    "V": "...-", "W": ".--", "X": "-..-", "Y": "-.--", "Z": "--..", "1": ".----",
+    "2": "..---", "3": "...--", "4": "....-", "5": ".....", "6": "-....", "7": "--...",
+    "8": "---..", "9": "----.", "0": "-----", "&": ".-...", "@": ".--.-.",
+    ":": "---...", ",": "--..--", ".": ".-.-.-", "'": ".----.", '"': ".-..-.",
+    "?": "..--..", "/": "-..-.", "=": "-...-", "+": ".-.-.", "-": "-....-",
+    "(": "-.--.", ")": "-.--.-", "!": "-.-.--", " ": "/"
+}  # Exclamation mark is not in ITU-R recommendation
+# fmt: on
+REVERSE_DICT = {value: key for key, value in MORSE_CODE_DICT.items()}
+
+
+def encrypt(message: str) -> str:
+    """
+    >>> encrypt("Sos!")
+    '... --- ... -.-.--'
+    >>> encrypt("SOS!") == encrypt("sos!")
+    True
+    """
+    return " ".join(MORSE_CODE_DICT[char] for char in message.upper())
+
+
+def decrypt(message: str) -> str:
+    """
+    >>> decrypt('... --- ... -.-.--')
+    'SOS!'
+    """
+    return "".join(REVERSE_DICT[char] for char in message.split())
+
+
+def main() -> None:
+    """
+    >>> s = "".join(MORSE_CODE_DICT)
+    >>> decrypt(encrypt(s)) == s
+    True
+    """
+    message = "Morse code here!"
+    print(message)
+    message = encrypt(message)
+    print(message)
+    message = decrypt(message)
+    print(message)
+
+
+if __name__ == "__main__":
+    main()