diff --git a/test/test_module.py b/test/test_module.py
new file mode 100644
index 0000000..0a55753
--- /dev/null
+++ b/test/test_module.py
@@ -0,0 +1,16 @@
+import os
+import pytest
+import updater
+from unittest import mock
+
+@pytest.mark.parametrize("system", [("Windows", "Linux", "Darwin")])
+def test_find_datafiles(system):
+    with mock.patch("platform.system", return_value=system):
+        result = updater.find_datafiles()
+        if system == "Windows":
+            assert "bootstrap.exe" in result[0][1]
+            assert os.path.exists(result[0][1][0])
+        else:
+            assert len(result[0][1]) == 2
+            assert os.path.exists(result[0][1][0])
+            assert os.path.exists(result[0][1][1])
\ No newline at end of file
diff --git a/updater/__init__.py b/updater/__init__.py
index 5b99436..a231cfe 100644
--- a/updater/__init__.py
+++ b/updater/__init__.py
@@ -1,8 +1,14 @@
 import glob
 import os.path
 import platform
+from typing import List, Tuple
 
-def find_datafiles():
+def find_datafiles() -> List[Tuple[str, List[str]]]:
+    """ Returns path to the updater bootstrap file.
+
+    :returns: A tuple of the form ("", ["bootstrap_file"])
+    :rtype: tuple
+    """
     system = platform.system()
     if system == 'Windows':
         file_ext = '*.exe'