diff --git a/.github/workflows/pytest_ci.yaml b/.github/workflows/pytest_ci.yaml
new file mode 100644
index 0000000..a13d4f2
--- /dev/null
+++ b/.github/workflows/pytest_ci.yaml
@@ -0,0 +1,26 @@
+name: Python CI
+
+on: push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+
+    - name: Set up Python
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.11
+        architecture: x64
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install -r requirements.txt
+
+    - name: Run tests with pytest
+      run: |
+        python -m pytest
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..e079f8a
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1 @@
+pytest
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_add.py b/tests/test_add.py
new file mode 100644
index 0000000..f9406a1
--- /dev/null
+++ b/tests/test_add.py
@@ -0,0 +1,14 @@
+import pytest
+from typing import Union
+
+from main import add
+
+
+@pytest.mark.parametrize(
+    "a, b, expected",
+    [(1, 2, 3), (1.0, 2.0, 3.0), (1, 2.0, 3.0), (1.0, 2, 3.0), (0, 0, 0), (-1, -1, -2)],
+)
+def test_add(a: Union[int, float], b: Union[int, float], expected: Union[int, float]):
+    result = add(a, b)
+
+    assert result == expected