diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 00000000..b0792c99
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,27 @@
+name: Unittests
+
+on: [pull_request]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.9", "3.10", "3.11"]
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install --upgrade pip setuptools wheel
+          python -m pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cpu
+          python -m pip install -e .
+      - name: Display Python version
+        run: python -m unittest discover -s tests/unit
diff --git a/chebai/preprocessing/structures.py b/chebai/preprocessing/structures.py
index 1e384598..1fb3711a 100644
--- a/chebai/preprocessing/structures.py
+++ b/chebai/preprocessing/structures.py
@@ -2,7 +2,6 @@
 
 import networkx as nx
 import torch
-from torch.utils.data.dataset import T_co
 
 
 class XYData(torch.utils.data.Dataset):
@@ -23,7 +22,7 @@ def __init__(
         self.x = x
         self.y = y
 
-    def __getitem__(self, index: int) -> T_co:
+    def __getitem__(self, index: int):
         """Returns the data and target at the given index."""
         return self.x[index], self.y[index]