Add template calculator tests

Author: inoue0426

tests/test_calculator.py

@@ -0,0 +1,16 @@
+import pytest
+
+from src.python_dev import add, divide
+
+
+def test_add_returns_sum() -> None:
+    assert add(2, 3) == 5
+
+
+def test_divide_returns_quotient() -> None:
+    assert divide(10, 2) == 5
+
+
+def test_divide_rejects_zero_denominator() -> None:
+    with pytest.raises(ValueError, match="denominator must not be zero"):
+        divide(10, 0)