diff --git a/tdd/__init__.py b/tdd/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tdd/test_util.py b/tdd/test_util.py
new file mode 100644
index 0000000..f3ccf87
--- /dev/null
+++ b/tdd/test_util.py
@@ -0,0 +1,7 @@
+from tdd.util import add
+
+def test_add_1():
+    assert add(1, 1) == 2
+
+def test_add_2():
+    assert add(3, 17) == 20
diff --git a/tdd/util.py b/tdd/util.py
new file mode 100644
index 0000000..13a41e0
--- /dev/null
+++ b/tdd/util.py
@@ -0,0 +1,2 @@
+def add(number_1, number_2):
+    return number_1 + number_2