diff --git a/SprintLib/testers/Python3Tester.py b/SprintLib/testers/Python3Tester.py
index 550db6d..1274014 100644
--- a/SprintLib/testers/Python3Tester.py
+++ b/SprintLib/testers/Python3Tester.py
@@ -7,8 +7,9 @@ class Python3Tester(BaseTester):
     file = None
 
     def before_test(self):
+        no_files = [file.filename for file in self.solution.task.files]
         for file in listdir(self.solution.testing_directory):
-            if file.endswith(".py") and file != 'checker.py':
+            if file.endswith(".py") and file not in no_files:
                 self.file = file
                 break
         if self.file is None: