diff --git a/tests/test_coder.py b/tests/test_coder.py
index 445aab345..80a92f902 100644
--- a/tests/test_coder.py
+++ b/tests/test_coder.py
@@ -12,6 +12,7 @@ from aider import models
 from aider.coders import Coder
 from aider.dump import dump  # noqa: F401
 from aider.io import InputOutput
+from tests.utils import GitTemporaryDirectory
 
 
 class TestCoder(unittest.TestCase):
@@ -95,47 +96,44 @@ class TestCoder(unittest.TestCase):
         self.assertEqual(coder.abs_fnames, expected_files)
 
     def test_check_for_ambiguous_filename_mentions_of_longer_paths(self):
-        # Mock the IO object
-        mock_io = MagicMock()
+        with GitTemporaryDirectory():
+            io = InputOutput(pretty=False, yes=True)
+            coder = Coder.create(models.GPT4, None, io)
 
-        # Initialize the Coder object with the mocked IO and mocked repo
-        coder = Coder.create(models.GPT4, None, mock_io)
+            fname = Path("file1.txt")
+            fname.touch()
 
-        fname = Path("file1.txt")
-        fname.touch()
+            other_fname = Path("other") / "file1.txt"
+            other_fname.parent.mkdir(parents=True, exist_ok=True)
+            other_fname.touch()
 
-        other_fname = Path("other") / "file1.txt"
-        other_fname.parent.mkdir(parents=True, exist_ok=True)
-        other_fname.touch()
+            mock = MagicMock()
+            mock.return_value = set([str(fname), str(other_fname)])
+            coder.get_tracked_files = mock
 
-        mock = MagicMock()
-        mock.return_value = set([str(fname), str(other_fname)])
-        coder.get_tracked_files = mock
+            # Call the check_for_file_mentions method
+            coder.check_for_file_mentions(f"Please check {fname}!")
 
-        # Call the check_for_file_mentions method
-        coder.check_for_file_mentions(f"Please check {fname}!")
-
-        self.assertEqual(coder.abs_fnames, set([str(fname.resolve())]))
+            self.assertEqual(coder.abs_fnames, set([str(fname.resolve())]))
 
     def test_check_for_subdir_mention(self):
-        # Mock the IO object
-        mock_io = MagicMock()
+        with GitTemporaryDirectory():
+            io = InputOutput(pretty=False, yes=True)
+            coder = Coder.create(models.GPT4, None, io)
 
-        # Initialize the Coder object with the mocked IO and mocked repo
-        coder = Coder.create(models.GPT4, None, mock_io)
+            fname = Path("other") / "file1.txt"
+            fname.parent.mkdir(parents=True, exist_ok=True)
+            fname.touch()
 
-        fname = Path("other") / "file1.txt"
-        fname.parent.mkdir(parents=True, exist_ok=True)
-        fname.touch()
+            mock = MagicMock()
+            mock.return_value = set([str(fname)])
+            coder.get_tracked_files = mock
 
-        mock = MagicMock()
-        mock.return_value = set([str(fname)])
-        coder.get_tracked_files = mock
+            dump(fname)
+            # Call the check_for_file_mentions method
+            coder.check_for_file_mentions(f"Please check `{fname}`")
 
-        # Call the check_for_file_mentions method
-        coder.check_for_file_mentions(f"Please check `{fname}`")
-
-        self.assertEqual(coder.abs_fnames, set([str(fname.resolve())]))
+            self.assertEqual(coder.abs_fnames, set([str(fname.resolve())]))
 
     def test_get_commit_message(self):
         # Mock the IO object
diff --git a/tests/utils.py b/tests/utils.py
index 1629c4425..c1b589eea 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -1,5 +1,10 @@
+import os
 import tempfile
 
+import git
+
+from aider.dump import dump  # noqa: F401
+
 
 class IgnorantTemporaryDirectory:
     def __init__(self):
@@ -13,3 +18,29 @@ class IgnorantTemporaryDirectory:
             self.temp_dir.__exit__(exc_type, exc_val, exc_tb)
         except OSError:
             pass  # Ignore errors (Windows)
+
+
+class ChdirTemporaryDirectory(IgnorantTemporaryDirectory):
+    def __init__(self):
+        self.cwd = os.getcwd()
+        super().__init__()
+
+    def __enter__(self):
+        res = super().__enter__()
+        os.chdir(self.temp_dir.name)
+        return res
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        os.chdir(self.cwd)
+        super().__exit__(exc_type, exc_val, exc_tb)
+
+
+class GitTemporaryDirectory(ChdirTemporaryDirectory):
+    def __enter__(self):
+        res = super().__enter__()
+
+        repo = git.Repo.init()
+        repo.config_writer().set_value("user", "name", "Test User").release()
+        repo.config_writer().set_value("user", "email", "testuser@example.com").release()
+
+        return res