Summary - Advanced testing

Combine integration, supertest and coverage to write an API test suite.

Summary - Advanced testing

In this group you learned the advanced test tools of Node.js: writing tests with test and expect, testing Express in memory with supertest, protecting production with a test database, measuring coverage with jest --coverage, and writing E2E tests with Playwright.

Now you will combine these into a small test skeleton. The skeleton will contain a test call, an expect assertion, and a beforeEach cleaning step. This mini task shows how the test tools combine.

Test design

A test skeleton is this: cleaning with beforeEach, a test definition with test, an assertion with expect. In integration tests, an HTTP request is sent with supertest.

Flow: beforeEach(() => { /* cleaning */ }); test("user creation", () => { const result = createUser({ name: "Ayşe" }); expect(result.name).toBe("Ayşe"); });. This skeleton cleans before each test, defines a test, and asserts the result. In production, supertest is added for integration tests. On top of the test skeleton you can add coverage targets, CI/CD integration and E2E scenarios. This is the foundation of reliable software delivery.

Exercise Build the test skeleton

Define beforeEach(() => { console.log("Cleaned"); }). Define test("example", () => { expect(1+1).toBe(2); }). Print "Test system ready" with console.log.

Show example solution

beforeEach(() => {
  console.log("Cleaned");
});
test("example", () => {
  expect(1+1).toBe(2);
});
console.log("Test system ready");

Test yourself

What pieces does the test skeleton combine?
```
test + expect + beforeEach
```
- Only require
- test, expect and beforeEach
- Only console.log
- Only coverage
Show answer

test, expect and beforeEach — test + expect + beforeEach combine.
Match each tool to its role

test

Defines a test
expect

Does assertions
beforeEach

Cleans before each test
supertest

Tests Express in memory

Next lesson: Project design

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