CI: run tests for ch2 and ch3 with proper imports

Author: srikanthbaride

.github/workflows/python-tests.yml

@@ -1,50 +1,64 @@
-# .github/workflows/python-tests.yml
 name: Python (Chapters)
 
 on:
   push:
     branches: [ "main" ]
+    paths:
+      - "ch2_rl_formulation/**"
+      - "ch3_multi_armed_bandits/**"
+      - "ch4_dynamic_programming/**"
+      - "ch5_monte_carlo/**"
+      - ".github/workflows/python-tests.yml"
   pull_request:
+    branches: [ "main" ]
+    paths:
+      - "ch2_rl_formulation/**"
+      - "ch3_multi_armed_bandits/**"
+      - "ch4_dynamic_programming/**"
+      - "ch5_monte_carlo/**"
+      - ".github/workflows/python-tests.yml"
 
 jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
-        chapter: [ch2_rl_formulation, ch3_bandits]
+        python-version: ["3.10", "3.11", "3.12"]
+        chapter: [ch2_rl_formulation, ch3_multi_armed_bandits, ch4_dynamic_programming, ch5_monte_carlo]
+
+    env:
+      PYTHONPATH: ${{ github.workspace }}
 
     steps:
-      - uses: actions/checkout@v4
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
 
-      - uses: actions/setup-python@v5
+      - name: Cache pip
+        uses: actions/cache@v4
         with:
-          python-version: "3.10"
+          path: ~/.cache/pip
+          key: ${{ runner.os }}-py${{ matrix.python-version }}-${{ hashFiles('**/requirements*.txt') }}
+          restore-keys: |
+            ${{ runner.os }}-py${{ matrix.python-version }}-
 
-      - name: Install deps
+      - name: Install dependencies
+        shell: bash
         run: |
           python -m pip install --upgrade pip
-          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
-          if [ -f "${{ matrix.chapter }}/requirements.txt" ]; then \
-            pip install -r "${{ matrix.chapter }}/requirements.txt"; \
+          if [ -f requirements.txt ]; then python -m pip install -r requirements.txt; fi
+          if [ -f "${{ matrix.chapter }}/requirements.txt" ]; then
+            python -m pip install -r "${{ matrix.chapter }}/requirements.txt"
           fi
-          pip install pytest
-
-      - name: Make repo importable
-        run: echo "PYTHONPATH=${GITHUB_WORKSPACE}" >> $GITHUB_ENV
-
-      - name: Check if ${{ matrix.chapter }} has tests
-        id: has_tests
-        run: |
-          if compgen -G "${{ matrix.chapter }}/tests/**/*.py" > /dev/null; then
-            echo "exists=true" >> $GITHUB_OUTPUT
-          else
-            echo "exists=false" >> $GITHUB_OUTPUT
+          if [ -f "${{ matrix.chapter }}/requirements_ch3.txt" ]; then
+            python -m pip install -r "${{ matrix.chapter }}/requirements_ch3.txt"
           fi
+          python -m pip install pytest
 
-      - name: Run ${{ matrix.chapter }} tests
-        if: steps.has_tests.outputs.exists == 'true'
-        run: pytest -q ${{ matrix.chapter }}/tests
-
-      - name: Note skipped chapter
-        if: steps.has_tests.outputs.exists != 'true'
-        run: echo "No tests found for ${{ matrix.chapter }} — skipping."
+      - name: Run tests for ${{ matrix.chapter }}
+        run: python -m pytest -q ${{ matrix.chapter }}/tests