Add workflows file for running tests on datasets

Added a YAML file to run GitHub Actions test suite on the datasets in
the repository. The YAML file checks out the repository that handles the
generation and representation of the causal contextuality scenarios (and
more) and runs a test suite with PySpark and Pytest on the datasets in
this repository.

Author: MarkusBolinder

.github/workflows/tests.yml

@@ -0,0 +1,58 @@
+name: Validate datasets
+
+on:
+  push:
+    branches:
+      - main
+      - master
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  validate-datasets:
+    runs-on: ubuntu-latest
+    timeout-minutes: 120
+
+    steps:
+      - name: Checkout dataset repository
+        uses: actions/checkout@v4
+        with:
+          path: datasets
+
+      - name: Checkout Quantum Experiment Structures
+        uses: actions/checkout@v4
+        with:
+          repository: MarkusBolinder/quantum-experiment-structures
+          path: quantum-experiment-structures
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      # Spark requires Java
+      - name: Set up Java
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "17"
+
+      - name: Install Quantum Experiment Structures
+        working-directory: quantum-experiment-structures
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+
+      - name: Verify Spark installation
+        run: |
+          python -c "from pyspark.sql import SparkSession; \
+          spark=SparkSession.builder.master('local[2]').appName('test').getOrCreate(); \
+          print(spark.range(10).count()); \
+          spark.stop()"
+
+      - name: Run ensemble dataset tests
+        env:
+          QES_DATA_ROOT: ${{ github.workspace }}/datasets
+        working-directory: quantum-experiment-structures
+        run: |
+          pytest unittests/end_to_end_test.py -v