Fix paths in unit tests

unit_test/main_tests/conftest.py

@@ -1,6 +1,7 @@
 import os
 import subprocess
 import sys
+from pathlib import Path
 
 import pytest
 
@@ -18,7 +19,7 @@ class ArgsInterceptor:
         self.kwargs = kwargs
 
 
-MOCK_PACKAGE_DIR = 'some_package_dir'
+MOCK_PACKAGE_DIR = Path('some_package_dir')
 
 
 @pytest.fixture(autouse=True)
@@ -43,16 +44,16 @@ def fake_package_dir(monkeypatch):
     '''
     Monkey-patch enough for the main() function to run
     '''
-    real_os_path_exists = os.path.exists
+    real_path_exists = Path.exists
 
-    def mock_os_path_exists(path):
-        if path == os.path.join(MOCK_PACKAGE_DIR, 'setup.py'):
+    def mock_path_exists(path):
+        if path == MOCK_PACKAGE_DIR / 'setup.py':
             return True
         else:
-            return real_os_path_exists(path)
+            return real_path_exists(path)
 
-    monkeypatch.setattr(os.path, 'exists', mock_os_path_exists)
-    monkeypatch.setattr(sys, 'argv', ['cibuildwheel', MOCK_PACKAGE_DIR])
+    monkeypatch.setattr(Path, 'exists', mock_path_exists)
+    monkeypatch.setattr(sys, 'argv', ['cibuildwheel', str(MOCK_PACKAGE_DIR)])
 
 
 @pytest.fixture(params=['linux', 'macos', 'windows'])