Extracted main function.

main.py

@@ -40,7 +40,7 @@ class MoviesApp(App):
             self.root.ids.message.text = 'Database error: {exception}'.format(exception=exception)
 
 
-if __name__ == "__main__":
+def main():
     try:
         app = MoviesApp()
         app.run()
@@ -48,3 +48,7 @@ if __name__ == "__main__":
         print('Initial database connection failed!', file=stderr)
         print('Cause: {exception}'.format(exception=exception), file=stderr)
         exit(1)
+
+
+if __name__ == "__main__":
+    main()