Automatic jest test generation for GitHub PRs with dual AI review

Workflow: Automatic Unit Test Creator from GitHub 🏗️ Architecture Overview This workflow listens for GitHub pull-request events, analyzes changed React/TypeScript files, auto-generates Jest tests via AI, has them reviewed by a second AI pass, and posts suggestions back as PR comments: 1. GitHub Webhook → PR opened or updated 2. Fetch & Diff → Retrieve raw diff of changed files 3. Filter & Split → Isolate .tsx files & their diffs 4. Fetch File Contents → Provide full context for tests 5. Test Maker Agent → Generate Jest tests for diff hunks 6. Code Reviewer Agent → Refine tests for style & edge-cases 7. Post PR Comment → Sends suggested tests back to GitHub 📦 Node-by-Node Breakdown mermaid flowchart LR AWebhook: /github/pr-events --> BGitHub: Get PR B --> CFunction: Parse diffurl + owner/repo C --> DHTTP Request: GET diffurl D --> EFunction: Split on "diff --git" E --> FFilter: /\.tsx$/ F --> GGitHub: Get File Contents G --> HTest Maker Agent H --> ICode Reviewer Agent I --> JFunction: Build Comment Payload J --> KHTTP Request: POST to PR Comments Webhook: GitHub PR Events - Type: HTTP Webhook (/webhook/github/pr-events) - Subscribed Events: pullrequest.opened, pullrequest.synchronize GitHub: Get PR - Node: GitHub - Action: "Get Pull Request" - Inputs: owner, repo, pullnumber Function: Parse diffurl + owner/repo - Extracts: - diffurl (e.g. …/pulls/123.diff) - owner, repo, mergecommitsha HTTP Request: GET diffurl - Fetches unified-diff text for the PR. Function: Split on "diff --git" - Splits the diff into file-specific segments. Filter: /.tsx$/ - Keeps only segments where the file path ends with .tsx. GitHub: Get File Contents - For each .tsx file, fetches the latest blob via GitHub API. Test Maker Agent - Prompt: - "Generate Jest unit tests covering only the behaviors changed in these diff hunks." - Output: Raw Jest test code. Code Reviewer Agent - Reads file + generated tests - Prompt: - "Review and improve these tests for readability, edge-cases, and naming conventions." - Output: Polished test suite. Function: Build Comment Payload - Wraps tests in TypeScript fences: ts // generated tests… - Constructs JSON: json { "body": "<tests>" } HTTP Request: POST to PR Comments - URL: https://api.github.com/repos/{owner}/{repo}/issues/{pullnumber}/comments - Body: Contains the suggested tests. 🔍 Design Rationale & Best Practices Focused Diff Analysis - Targets only .tsx files to cover UI logic. Two-Stage AI - Separate "generate" + "review" steps mimic TDD + code review. Stateless Functions - Pure JS for parsing & transformation, easy to test. Non-Blocking PR Comments - Asynchronous suggestions—developers aren't blocked. Scoped Permissions - GitHub token limited to reading PRs & posting comments.