What is the difference between synchronous and asynchronous testing?

Question

Accepted Answer

**Synchronous** — wait for completion. **Asynchronous** — don't wait.

**Synchronous Testing:**
- Tests wait for results.
- Simple assertions.
- Predictable.
- May timeout.

```
Synchronous:
test("add", () => {
  const result = add(1, 2);
  expect(result).toBe(3);
});
(Immediate result)
```

**Asynchronous Testing:**
- Tests handle promises/callbacks.
- More complex assertions.
- May need async/await.
- Timeout handling.

```
Asynchronous:
test("fetch", async () => {
  const result = await fetchData();
  expect(result).toBeDefined();
});
(Handles promise)
```

**Key differences:**
- **Sync** — wait for result.
- **Async** — handle promise.
- **Sync** — simpler.
- **Async** — more complex.

Systems Analyst: What is the difference between synchronous and asynchronous testing?