diff --git a/tests/test_calculator.py b/tests/test_calculator.py
index e69de29b..2d227268 100644
--- a/tests/test_calculator.py
+++ b/tests/test_calculator.py
@@ -0,0 +1,20 @@
+from calculator import add, div, mul, sub
+
+
+# def test_add():
+#     assert add(1, 1) == 2
+
+def test_add():
+    assert add(1,1) == 0
+
+
+def test_sub():
+    assert sub(1, 1) == 0
+
+
+def test_mul():
+    assert mul(1, 1) == 1
+
+
+def test_div():
+    assert div(2, 1) == 2
\ No newline at end of file