Added unit tests for Shor’s Algorithm

- Created `tests/cryptography/test_shor_algorithm.py`
- Added test cases for different values of N (e.g., 15, 21, 35, 55)
- Used `pytest` to verify correct factorization
- Ensured factors returned are correct and non-trivial

Author: adityakrmishra

tests/cryptography/test_shor_algorithm.py

@@ -0,0 +1,12 @@
+import pytest
+from algorithms.cryptography.shor_algorithm import shor_algorithm
+
+@pytest.mark.parametrize("N, expected_factors", [
+    (15, (3, 5)),
+    (21, (3, 7)),
+    (35, (5, 7)),
+    (55, (5, 11)),
+])
+def test_shor_algorithm(N, expected_factors):
+    factors = shor_algorithm(N)
+    assert sorted(factors) == sorted(expected_factors), f"Failed for N={N}"