diff --git a/src/sample/simple.py b/src/sample/simple.py
new file mode 100644
index 00000000..c929f885
--- /dev/null
+++ b/src/sample/simple.py
@@ -0,0 +1,2 @@
+def add_one(number):
+    return number + 1
diff --git a/tests/test_simple.py b/tests/test_simple.py
index 61e44ebc..b7a0ee3a 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -2,6 +2,16 @@
 # testing in general, but rather to support the `find_packages` example in
 # setup.py that excludes installing the "tests" package
 
+import unittest
 
-def test_success():
-    assert True
+from sample.simple import add_one
+
+
+class TestSimple(unittest.TestCase):
+
+    def test_add_one(self):
+        self.assertEqual(add_one(5), 6)
+
+
+if __name__ == '__main__':
+    unittest.main()