Fix: missing build tools for numpy due to caching

.github/workflows/ci.yml

@@ -3,11 +3,10 @@ name: CI
 on: [push, pull_request]
 
 jobs:
-  build:
+  test:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        # Define the specific versions you want to test against
         python-version: ["3.10", "3.11", "3.12", "3.13"]
     steps:
       - uses: actions/checkout@v4
@@ -21,9 +20,7 @@ jobs:
       - name: Install Dependencies
         run: |
           pip install --upgrade pip
-          # Install pinned dependencies first for reproducibility
           if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-          # Install the project in editable mode + dev tools
           pip install -e ".[dev]"
 
       - name: Lint & Format Check (Ruff)
@@ -36,6 +33,24 @@ jobs:
           bandit -c pyproject.toml -r .
 
       - name: Run Tests with Coverage
-        # pytest will read config from pyproject.toml
         run: |
-          pytest
+          pytest
+
+  docker:
+    needs: test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build Docker Image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          file: Dockerfile
+          push: false
+          tags: project-image:latest
+          cache-from: type=gha
+          cache-to: type=gha,mode=max

Dockerfile

@@ -9,7 +9,9 @@ WORKDIR /app
 
 USER root
 
-RUN apt-get update && apt-get upgrade -y && apt-get clean && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get upgrade -y && \
+    apt-get install -y --no-install-recommends gcc g++ pkg-config && \
+    apt-get clean && rm -rf /var/lib/apt/lists/*
 
 RUN groupadd -r nonroot_usr && useradd -r -g nonroot_usr nonroot_usr