diff --git a/tests/test_cargo_install.py b/tests/test_cargo_install.py
index b29e025..5fca12e 100644
--- a/tests/test_cargo_install.py
+++ b/tests/test_cargo_install.py
@@ -7,24 +7,29 @@
     validate_library_name,
 )
 
+
 def test_find_cargo_toml_exists(tmp_path, mock_os_path_exists):
     (tmp_path / "Cargo.toml").touch()
     mock_os_path_exists.return_value = True
     result = find_cargo_toml(str(tmp_path))
     assert result == str(tmp_path / "Cargo.toml")
 
+
 def test_find_cargo_toml_not_found():
     result = find_cargo_toml()
     assert result is None
 
+
 def test_validate_library_name_valid():
     assert validate_library_name("serde") is True
 
+
 def test_validate_library_name_invalid(capsys):
     assert validate_library_name("serde;malicious") is False
     captured = capsys.readouterr()
     assert "Invalid library name: serde;malicious" in captured.out
 
+
 def test_check_cargo_installed(mock_shutil_which, capsys):
     mock_shutil_which.return_value = "/usr/bin/cargo"
     assert check_cargo_installed() is True
@@ -34,19 +39,26 @@ def test_check_cargo_installed(mock_shutil_which, capsys):
     captured = capsys.readouterr()
     assert "cargo is not installed or not found in PATH" in captured.out
 
-def test_cargo_install_success(tmp_path, mock_subprocess_run,  mock_os_chdir, capsys):
+
+def test_cargo_install_success(tmp_path, mock_subprocess_run, mock_os_chdir, capsys):
     (tmp_path / "Cargo.toml").touch()
-    mock_subprocess_run.return_value = MagicMock(returncode=0, stdout="Added serde", stderr="")
+    mock_subprocess_run.return_value = MagicMock(
+        returncode=0, stdout="Added serde", stderr=""
+    )
     cargo_install(["serde"])
     captured = capsys.readouterr()
     assert "Running cargo add serde ..." in captured.out
     assert "Cargo output:\nAdded serde" in captured.out
     mock_os_chdir.assert_called()
 
-def test_cargo_install_failure(tmp_path, mock_subprocess_run,  capsys):
+
+def test_cargo_install_failure(tmp_path, mock_subprocess_run, capsys):
     (tmp_path / "Cargo.toml").touch()
     mock_subprocess_run.side_effect = subprocess.CalledProcessError(
-        returncode=1, cmd=["cargo", "add", "serde"], output="", stderr="Error: invalid crate"
+        returncode=1,
+        cmd=["cargo", "add", "serde"],
+        output="",
+        stderr="Error: invalid crate",
     )
     cargo_install(["serde"])
     captured = capsys.readouterr()
@@ -54,4 +66,3 @@ def test_cargo_install_failure(tmp_path, mock_subprocess_run,  capsys):
         raise AssertionError
     if "stderr:\nError: invalid crate" not in captured.out:
         raise AssertionError
-