Add unit tests for factorial.py

maths/test_factorial.py

@@ -0,0 +1,37 @@
+# /// script
+# requires-python = ">=3.13"
+# dependencies = [
+#     "pytest",
+# ]
+# ///
+
+import pytest
+
+from maths.factorial import factorial, factorial_recursive
+
+
+@pytest.mark.parametrize("function", [factorial, factorial_recursive])
+def test_zero(function):
+    assert function(0) == 1
+
+
+@pytest.mark.parametrize("function", [factorial, factorial_recursive])
+def test_positive_integers(function):
+    assert function(1) == 1
+    assert function(5) == 120
+    assert function(7) == 5040
+
+
+@pytest.mark.parametrize("function", [factorial, factorial_recursive])
+def test_large_number(function):
+    assert function(10) == 3628800
+
+
+@pytest.mark.parametrize("function", [factorial, factorial_recursive])
+def test_negative_number(function):
+    with pytest.raises(ValueError):
+        function(-3)
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])