Progress 4GL

Test Primo Anavar First Cycle Questions Pharma TRT

Below is a practical "cheat‑sheet" of what each of the standard unit‑test files you’ll see in a typical Node/JavaScript repo actually checks for, and why a test might be failing even when the code looks fine.
It’s written with a "why it fails / how to fix it" mindset so that you can debug faster.

---

## 1. `index.js` (or whatever your main entry point is)

| What the tests usually verify | Typical reasons for failure |
|-------------------------------|-----------------------------|
| *Exports* – that all public functions/objects are exported correctly (`module.exports = foo, bar `). | 1️⃣ Export typo or steroid friendly doctors - www.valley.md, missing property.
2️⃣ Circular require that ends up exporting `undefined`. |
| *Default export* – if you’re using ES‑modules (`export default MyClass`). | Wrong import syntax in tests (`require` vs `import`). |
| *Side‑effects on load* – e.g., global configuration, logging. | Global state mutation causes tests to fail in isolation (use mocks). |

> **Tip**: Use a small "index" file that only re‑exports and keep heavy logic in separate modules.

---

### 2️⃣ Core API Functions / Methods

| Category | Typical Tests |
|----------|---------------|
| **Synchronous functions** | - Return type is correct.
- Throws the right error for bad input.
- Handles edge cases (empty array, null). |
| **Asynchronous functions** (`async/await` or callbacks) | - Resolves with expected value.
- Rejects on errors.
- Timeout / cancellation behavior. |
| **Stateful methods** (e.g., classes that mutate internal state) | - State changes as expected after calls.
- No unintended side‑effects. |

#### Example: `calculateSum(numbers: number): number`

```ts
describe('calculateSum', () =>
it('returns sum of numbers', () =>
expect(calculateSum(1,2,3)).toBe(6);
);
it('handles empty array', () =>
expect(calculateSum()).toBe(0);
);
);
```

#### Example: Async Function `fetchData(url)`

```ts
describe('fetchData', () =>
it('returns data when resolved', async () =>
const result = await fetchData('https://api.example.com');
expect(result).toHaveProperty('data');
);

it('rejects on error', async () =>
await expect(fetchData('bad-url')).rejects.toThrow();
);
);
```

---

## 5. Summary

| Section | Key Points |
|---------|------------|
| **Project Setup** | Use `create-react-app` → install dependencies (`react-router-dom`, `axios`) |
| **App Architecture** | Functional components, React Router for navigation, Axios for API requests |
| **Components** | Navbar (links), Home (fetch & list), PostDetail (show post + comments) |
| **Data Flow** | Fetch on mount with `useEffect`; store in state; pass data via props or route params |
| **Routing** | `/` → Home, `/posts/:id` → PostDetail |
| **Error Handling** | Try/catch for API calls, display messages |
| **Styling** | Simple CSS (optional Bootstrap) |

This outline provides a clear plan to implement the requested blog post viewer using React. The actual code would follow this structure: create `App.js`, add `Navbar`, `Home`, and `PostDetail` components, implement fetch logic with Axios or Fetch API, handle routing with React Router, and style accordingly.