Backported from upstream commit 57e16ce3d92067c6246c3de04f2d4b9803f6f25b

--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -44,7 +44,7 @@ class MainAPITests(unittest.TestCase):
         with open(LEFT_FILE, "rb") as infile:
             with open(RIGHT_FILE, "rb") as infile:
                 # Give something else, and it fails:
-                with self.assertRaises(ValueError):
+                with self.assertRaises(TypeError):
                     main.diff_texts(infile, infile)
 
     def test_api_diff_trees(self):