lesson

Mocking & Test Doubles

27 / 47

35 minlesson

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1 min read

Isolate units with mocks, stubs, and spies. Mock external dependencies so tests don't depend on APIs, databases, or other services.

What You'll Learn

class UserRepository {
  getUser(id) { /* database call */ }
}

class UserService {
  constructor(repo) { this.repo = repo; }
// ...

You completed the free preview — you are ready for the full path.

All lessons are readable below. To write and run code from lesson 11 onwards, upgrade to Path Plus ($9/mo) or Pro.

1 min read

Isolate units with mocks, stubs, and spies. Mock external dependencies so tests don't depend on APIs, databases, or other services.

class UserRepository {
  getUser(id) { /* database call */ }
}

class UserService {
  constructor(repo) { this.repo = repo; }
// ...

1 min read

Isolate units with mocks, stubs, and spies. Mock external dependencies so tests don't depend on APIs, databases, or other services.

class UserRepository {
  getUser(id) { /* database call */ }
}

class UserService {
  constructor(repo) { this.repo = repo; }
// ...

1 min read

Isolate units with mocks, stubs, and spies. Mock external dependencies so tests don't depend on APIs, databases, or other services.

class UserRepository {
  getUser(id) { /* database call */ }
}

class UserService {
  constructor(repo) { this.repo = repo; }
// ...