src/codewars/kata_ceasar_cipher_helper.py

@@ -0,0 +1,28 @@
+class CaesarCipher(object):
+    def __init__(self, shift):
+        self.shift = shift
+        self.alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+    def encode(self, text):
+        idx_alph = [
+            self.alphabet.index(x) if x in self.alphabet else x for x in text.upper()
+        ]
+        idx_shift = [
+            (x + self.shift) % len(self.alphabet) if isinstance(x, (int)) else x
+            for x in idx_alph
+        ]
+        return "".join(
+            [self.alphabet[x] if isinstance(x, (int)) else x for x in idx_shift]
+        )
+
+    def decode(self, text):
+        idx_alph = [
+            self.alphabet.index(x) if x in self.alphabet else x for x in text.upper()
+        ]
+        idx_shift = [
+            (x - self.shift) % len(self.alphabet) if isinstance(x, (int)) else x
+            for x in idx_alph
+        ]
+        return "".join(
+            [self.alphabet[x] if isinstance(x, (int)) else x for x in idx_shift]
+        )

tests/codewars/test_ceasar_cipher_helper.py

@@ -0,0 +1,8 @@
+from src.codewars.kata_ceasar_cipher_helper import CaesarCipher
+
+
+def test_cipher_helper():
+    c = CaesarCipher(5)
+
+    assert c.encode("Codewars") == "HTIJBFWX"
+    assert c.decode("HTIJBFWX") == "CODEWARS"

tests/codewars/test_vigenere_cipher_helper.py

@@ -1,4 +1,4 @@
-from src.codewars.kata_cipher_helper import VigenereCipher
+from src.codewars.kata_vigenere_cipher_helper import VigenereCipher
 
 
 def test_cipher_helper():