Apa iku integration testing?

Question

Accepted Answer

**Integration testing** neverifikasi manawa akèh **komponen utawa unit bisa ana bebarengan kanthi bener** — ngetèst interaksi lan titik integrasi (kaya kode karo database, layanan sing saling memanggil, utawa modul sing digabungake). Iku nyedhak masalah sing unit test (sing ngisolasi unit) keliru.

## Apa sing diverifikasi integration testing

```text
Integration tests verify COMPONENTS WORKING TOGETHER (not in isolation):
  → code + DATABASE (does the data layer actually work with a real DB?)
  → service A calling service B / an external API
  → multiple modules/units combined; the integration POINTS between them
→ catches issues in how parts INTERACT — which unit tests (isolated) can't catch.
```

## Mengapa integration test penting (lawan unit test)

```text
UNIT tests isolate units (mocking dependencies) → fast, but DON'T verify real integration:
  → a unit can pass its tests but FAIL when combined (wrong assumptions about a dependency,
    a real DB query that's wrong, an API contract mismatch, config issues)
INTEGRATION tests use REAL (or realistic) dependencies → catch these interaction bugs:
  → wiring/configuration errors, data layer issues, contract mismatches between components
→ Integration tests verify the parts actually work TOGETHER.
```

## Conto lan pertimbangan

```js
// integration test: the repository actually works with a (test) database
test('UserRepository saves and retrieves a user', async () => {
  const repo = new UserRepository(testDb);     // REAL test database
  await repo.save({ name: 'Ann' });
  const user = await repo.findByName('Ann');    // real query
  expect(user.name).toBe('Ann');
});
```

```text
→ SLOWER than unit tests (real I/O, setup); use a TEST database/environment
→ Test important integration points (data access, key service interactions, APIs)
→ Fewer than unit tests (the pyramid middle); manage test data/state carefully
```

## Mengapa iku penting

Ngerteni integration testing kuwi penting amarga iku **nyedhak golongan cacat sing unit test ora bisa** — masalah carane komponen bebarengan — dadi iku katrangan kawicaksanan sing berharga kanggo ngetèst kanthi lengkap.

Sanajan unit test neverifikasi unit siji-sijine kanthi asing (mocking dependencies), isolasi iki nandha yen iku **ora bisa neverifikasi integrasi nyata**: unit bisa lolos kabèh tesine dene gagal nalika digabungake karo liyane (amarga anggapan salah babagan dependency, query database nyata sing salah, API contract mismatch, utawa masalah konfigurasi). **Integration test** ngeisi jurang iki kanthi ngetèst **komponen bebarengan karo dependency nyata (utawa realistis)** — neverifikasi manawa kode pancen bisa karo database nyata, manawa layanan berinteraksi kanthi bener, lan manawa titik integrasi fungsi — nyedhak wiring, data-layer, lan contract cacat sing unit test sing asing keliru.

Ngerteni hubungan komplementer iki (unit test kanggo logika sing asing, integration test kanggo interaksi nyata) iku kunci ngetèst kanthi lengkap, amarga ora ana siji pun cukup.

Ngerteni **pertimbangan** — manawa integration test luwih alon (I/O nyata lan setup, dadi iku ana ing tengah piramida karo suwe saka unit test), nggunakaké test database/environment, fokus ing titik integrasi penting (data access, interaksi layanan kunci, API), lan perlu manajemen data test/state sing teliti — ngrèflèksi integration testing praktis.

Integration test menehi kapercayan manawa parts sing dirakit bisa ana bebarengan, apa sing unit test piyé ora bisa menehi.

Sanajan aplikasi nyata diwutuh saka komponen sing berinteraksi lan integration cacat (masalah database, contract mismatch, kesalahan konfigurasi) umum lan nglèwal saka unit test, lan sanajan integration testing nyedhak iku kanthi neverifikasi komponen bebarengan, ngerteni integration testing kuwi katrangan kawicaksanan sing berharga lan praktis — pelengkap penting kanggo unit testing sing nyedhak interaksi cacat, penting kanggo ngetèst kanthi lengkap sing neverifikasi ora mung unit sing asing dene manawa sistem parts pancen bisa bebarengan kanthi bener.