diff --git a/unit_test.py b/unit_test.py
new file mode 100644
index 00000000..418e11bc
--- /dev/null
+++ b/unit_test.py
@@ -0,0 +1,20 @@
+# file: test_calculator_unittest.py
+import unittest
+from calculator import add, divide
+
+class TestCalculator(unittest.TestCase):
+
+    def test_add(self):
+        self.assertEqual(add(2, 3), 5)
+        self.assertEqual(add(-1, 1), 0)
+
+    def test_divide(self):
+        self.assertEqual(divide(10, 2), 5)
+        self.assertAlmostEqual(divide(7, 3), 2.3333, places=4)
+
+    def test_divide_by_zero(self):
+        with self.assertRaises(ValueError):
+            divide(5, 0)
+
+if __name__ == "__main__":
+    unittest.main()