Apa iku Test-Driven Development (TDD)?

Question

Accepted Answer

**Test-Driven Development (TDD)** minangka praktek ing mana sampeyan nulis **test sadurunge kode** — ngetutake siklus sing cendhak lan mbalekake: nulis test sing gagal, nulis kode kanggo nglaloni, banjur refactor. Iku nggedhekake desain liwat test lan njamin kode iku testable lan teruji kanthi apik.

## Siklus TDD: Red, Green, Refactor

```text
1. RED → write a FAILING test for the behavior you want (it fails — the code doesn't exist yet)
2. GREEN → write the MINIMUM code to make the test PASS (just enough, don't over-build)
3. REFACTOR → improve/clean up the code (and tests) while keeping tests GREEN
→ Repeat this short cycle for each small piece of behavior.
```

```text
Write test (RED) → write code (GREEN) → clean up (REFACTOR) → repeat
```

## Contoh alur

```js
// 1. RED — write the test first (fails: add doesn't exist / is wrong)
test('add(2,3) === 5', () => expect(add(2, 3)).toBe(5));

// 2. GREEN — write minimal code to pass
function add(a, b) { return a + b; }

// 3. REFACTOR — improve if needed (test still passes); then write the next test
```

## Manfaat lan pertimbangan

```text
✓ Ensures code is TESTABLE (you design for testing) and TESTED (tests exist by definition)
✓ Drives DESIGN — thinking about behavior/interface first → cleaner, focused code
✓ Fast FEEDBACK; confidence to refactor; avoids over-engineering (write only what's needed)
✓ Good test coverage as a natural result
⚠️ A discipline/skill that takes practice; not always applied dogmatically (use judgment)
```

## Ngapa iku penting

Pamahaman Test-Driven Development iku berharga amarga iku **praktek sing berpengaruh, luwes didiskusikake** sing mbentuk cara akeh developer ngadhepi testing lan desain, mula penting banget pengetahuan kanggo pangembangan profesional.

Ide pokok TDD — **nulis test sadurunge kode**, ngetutake **siklus Red-Green-Refactor** (nulis test sing gagal, nulis kode minimal kanggo nglaloni, banjur refactor nalika tetep green) — iku pendekatan sing beda sing mbalikaké urutan biasane.

Pamahaman siklus iku pengetahuan praktis kunci.

Pamahaman **manfaat** nerangake apa TDD dihargai: njamin kode iku **testable** (ngrancang kanggo testing saka awal) lan **teruji** (test ana ing definisi), **nggedhekake desain** (mikir babagan perilaku lan interface pisanan nyebabake kode sing luwih rapi, luwih fokus), menehi umpan balik cepet lan kepercayaan kanggo refactor, nggegan over-engineering (nulis mung apa sing perlu kanggo nglaloni test), lan asik-asikan ngasilake coverage test sing apik.

Manfaat iki nyebabake TDD berpengaruh minangka praktek testing lan desain.

Pamahaman **pertimbangan** — yen TDD iku disiplin sing butuh latihan, lan ora tansah diterapake secara dogmatis (developer nggunakake pertimbangan ngenani kapan iku cocok) — nggambarake pandangan sing seimbang, realistis.

Sakabehe developer sing ora tansah nglakoni TDD entuk kauntungan saka pamahaman iki, amarga iku membentuk pamikiran ngenani testing lan desain lan iku topik umum ing pangembangan profesional lan interview.

Kenging TDD iku praktek berpengaruh, luwes dimangerteni sing mbentuk pendekatan testing lan desain (kanthi manfaat nyata ing testability, desain, lan coverage) lan iku topik profesional lan interview umum, lan kenging pamahaman siklus, manfaat, lan pertimbangan nggambarake kematangan testing, pamahaman Test-Driven Development iku pengetahuan berharga, relevan — praktek testing lan filosofi penting kanggo dimangerteni pangembangan profesional, berpengaruh ing cara developer sing ngutamakake kualitas ngerancang perangkat lunak.