Learning Outcomes

• Author unit tests using JUnit 5
• Understand CI as a quality gate
• Observe how pipelines catch regressions
• Practice fix-validate-ship workflow

Overview

You will implement a small Java program, write a test suite, and validate the system through an automated GitHub Actions pipeline. Your main job is to ship a green build!

Part 0 — Clone and Run

Accept the GitHub Classroom assignment: Clone the repository. Run the project: mvn -B test

Part 1 — Create and Trigger a CI/CD Pipeline

Inside your repository, create the folder structure:

.github/
   workflows/
    ci.yaml

Add the following baseline pipeline:

name: Java CI

on:
  push:
    branches: ["main"]
  pull_request:
    branches: ["main"]

jobs:
  build-test:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Set up Java 21
        uses: actions/setup-java@v4
        with:
          java-version: '21'
          distribution: 'temurin'

      - name: Build
        run: mvn -B package

      - name: Test
        run: mvn -B test

Commit and push your file (ci.yaml). This should trigger a pipeline run in GitHub Actions: GitHub → Your Repo → Actions

Ensure that the pipeline runs and results in a green checkmark!

Part 2 — Implement PlaylistRecommender

Open src/main/java/edu/pitt/se/PlaylistRecommender.java and implement the three methods:

• classifyEnergy(List<Integer> bpms)
  • Return "HIGH" if avg BPM ≥ 140
  • "MEDIUM" if 100–139
  • "LOW" if < 100
  • Reject null or empty lists
• isValidTrackTitle(String title)
  • Checks for alphabetic characters + spaces, 1–30 chars
  • Reject null or special characters
• normalizeVolume(int volumeDb)
  • Clamp volume into range 0–100 (e.g., 120 -> 100, -10 -> 0)

Part 3 — Write Tests in PlaylistRecommenderTest.java

Open src/test/java/edu/pitt/se/PlaylistRecommenderTest.java and implement at least one test case per method.

Part 4 — Inspect CI/CD pipeline

Complete the pipeline and ensure that test cases are executed during every build.

Your goal: All tests must pass (=green checkmark = shippable build).