diff --git a/.github/workflows/pytest.yml b/.github/workflows/pytest.yml
new file mode 100644
index 0000000..1ef7eac
--- /dev/null
+++ b/.github/workflows/pytest.yml
@@ -0,0 +1,38 @@
+name: Pytest Tests
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.9", "3.10", "3.11", "3.12"]
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+        cache: 'pip'
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements.txt
+        pip install pytest pytest-cov
+
+    - name: Run tests
+      run: |
+        pytest tests/ -v --cov=src --cov-report=xml --cov-report=html
+
+    - name: Upload test results
+      uses: actions/upload-artifact@v4
+      if: always()
+      with:
+        name: pytest-results-${{ matrix.python-version }}
+        path: |
+          junit.xml
+          htmlcov/
\ No newline at end of file
diff --git a/src/jrdev/commands/model.py b/src/jrdev/commands/model.py
index bf77499..d9c7397 100644
--- a/src/jrdev/commands/model.py
+++ b/src/jrdev/commands/model.py
@@ -4,7 +4,7 @@
 Model command implementation for the JrDev terminal.
 Manages the user's list of available models and the active chat model.
 """
-from typing import Any, List
+from typing import Any, List, Union
 
 from jrdev.ui.ui import PrintType
 from jrdev.utils.string_utils import is_valid_context_window, is_valid_cost, is_valid_name
@@ -22,7 +22,7 @@ def _parse_bool(val: str) -> bool:
 
 
 # pylint: disable=too-many-return-statements
-def _parse_model_arguments(app, args: List[str], start_idx: int) -> dict | None:
+def _parse_model_arguments(app, args: List[str], start_idx: int) -> Union[dict, None]:
     """Parse and validate model arguments starting from given index."""
     name = args[start_idx]
     provider = args[start_idx + 1]
diff --git a/src/jrdev/file_operations/confirmation.py b/src/jrdev/file_operations/confirmation.py
index 3f28c35..f5d3681 100644
--- a/src/jrdev/file_operations/confirmation.py
+++ b/src/jrdev/file_operations/confirmation.py
@@ -1,5 +1,5 @@
 import os
-from typing import Optional, Tuple
+from typing import Optional, Tuple, Union
 
 from jrdev.file_operations.diff_markup import apply_diff_markup, remove_diff_markup
 from jrdev.file_operations.diff_utils import create_diff
@@ -91,7 +91,7 @@ async def write_file_with_confirmation(app, filepath: str, content: str):
     return 'no', None
 
 
-async def write_with_confirmation(app, filepath: str, content: list | str) -> Tuple[str, str]:
+async def write_with_confirmation(app, filepath: str, content: Union[list, str]) -> Tuple[str, Optional[str]]:
     if isinstance(content, list):
         content_str = ''.join(content)
     else: