diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
index b859c1b..4bcb997 100644
--- a/.github/workflows/pytest.yml
+++ b/.github/workflows/pytest.yml
@@ -7,21 +7,35 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
 
     steps:
       - uses: actions/checkout@v2
+
+      - name: Set up WSL
+        if: matrix.os == 'windows-latest'
+        uses: Vampire/setup-wsl@v2
+        with:
+          distribution: 'Ubuntu-20.04'
+          use-cache: 'true'
+          update: 'true'
+          additional-packages: 'python3-pip'
+          wsl-shell-user: 'root'
+
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python-version }}
+
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
           pip install -e ".[test,docs]"
+
       - name: Run pytest
         run: pytest
+
       - name: Upload coverage reports to Codecov
         if: matrix.os == 'ubuntu-latest' && matrix.python-version == '3.11'
         uses: codecov/codecov-action@v3
diff --git a/rsync_time_machine.py b/rsync_time_machine.py
index 5bc46a0..08f8e0a 100755
--- a/rsync_time_machine.py
+++ b/rsync_time_machine.py
@@ -8,8 +8,9 @@
 import sys
 import time
 from datetime import datetime
+from pathlib import Path
 from types import FrameType
-from typing import Dict, List, NamedTuple, Optional, Tuple
+from typing import Dict, List, NamedTuple, Optional, Tuple, Union
 
 APPNAME = "rsync-time-machine.py"
 VERBOSE = False
@@ -322,12 +323,12 @@ def expire_backups(
                 break
 
 
-def backup_marker_path(folder: str) -> str:
+def backup_marker_path(folder: Union[str, Path]) -> Path:
     """Return the path to the backup marker file."""
-    return os.path.join(folder, "backup.marker")
+    return Path(folder) / "backup.marker"
 
 
-def find_backup_marker(folder: str, ssh: Optional[SSH]) -> Optional[str]:
+def find_backup_marker(folder: str, ssh: Optional[SSH]) -> Optional[Union[str, Path]]:
     """Find the backup marker file in the given folder."""
     marker_path = backup_marker_path(folder)
     output = find(marker_path, ssh)
@@ -375,7 +376,7 @@ def run_cmd(
     return CmdResult(result.stdout.strip(), result.stderr.strip(), result.returncode)
 
 
-def find(path: str, ssh: Optional[SSH]) -> str:
+def find(path: Union[str, Path], ssh: Optional[SSH]) -> str:
     """Find files in the given path, using the `find` command."""
     return run_cmd(f"find '{path}'", ssh).stdout
 
diff --git a/tests/test_app.py b/tests/test_app.py
index 0ed82f9..713a8a1 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -178,7 +178,8 @@ def test_find_backups(tmp_path: Path) -> None:
 
 def test_backup_marker_path() -> None:
     """Test the backup_marker_path function."""
-    assert backup_marker_path("/path/to/folder") == "/path/to/folder/backup.marker"
+    folder = Path("path") / "to" / "folder"
+    assert backup_marker_path(folder) == folder / "backup.marker"
 
 
 def test_find_backup_marker(tmp_path: Path) -> None: