Handle missing filename when only 1 in session

tests/test_wholefile.py

@@ -68,6 +68,42 @@ class TestWholeFileCoder(unittest.TestCase):
                 updated_content = f.read()
             self.assertEqual(updated_content, "Updated content\n")
 
+    def test_update_files_earlier_filename(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            os.chdir(temp_dir)
+
+            sample_file = "accumulate.py"
+            content = (
+                "def accumulate(collection, operation):\n    return [operation(x) for x in"
+                " collection]\n"
+            )
+
+            with open(sample_file, "w") as f:
+                f.write("Original content\n")
+
+            # Initialize WholeFileCoder with the temporary directory
+            io = InputOutput(yes=True)
+            coder = WholeFileCoder(main_model=models.GPT35, io=io, fnames=[sample_file])
+
+            # Set the partial response content with the updated content
+            coder.partial_response_content = (
+                f"Here's the modified `{sample_file}` file that implements the `accumulate`"
+                f" function as per the given instructions:\n\n```\n{content}```\n\nThis"
+                " implementation uses a list comprehension to apply the `operation` function to"
+                " each element of the `collection` and returns the resulting list."
+            )
+
+            # Call update_files method
+            edited_files = coder.update_files()
+
+            # Check if the sample file was updated
+            self.assertIn(sample_file, edited_files)
+
+            # Check if the content of the sample file was updated
+            with open(sample_file, "r") as f:
+                updated_content = f.read()
+            self.assertEqual(updated_content, content)
+
 
 if __name__ == "__main__":
     unittest.main()