In this module, you’ll learn how to use narrow integration tests to drive the development of low-level infrastructure wrappers. You’ll build HttpClient, an infrastructure wrapper for HTTP-based services.

Concepts

Download the slides and transcript here.

Direct links to patterns discussed in this module:

• Infrastructure Wrappers
• Narrow Integration Tests

Primers

You may wish to familiarize yourself with these primers before starting on the exercises:

• JavaScript Basics
• JavaScript Concurrency
• Introduced in challenge #1:
  • await
  • Arrow Functions
  • Using Promises
  • Creating Promises
  • Using Events
• Introduced in challenge #7:
  • Object Shorthand
  • delete
• Introduced in challenge #8:
  • async
• Introduced in challenge #9:
  • String Interpolation
• Introduced in challenge #10:
  • Array Destructuring
• Introduced in challenge #11:
  • Object Destructuring
  • Default Function Parameters
  • Private Methods (#)

Exercise Setup

Start with the Overall Setup. Then:

1. Check out the code

1. Check out the exercise branch:
   • JavaScript: git checkout narrow-integration-tests-js
   • TypeScript: git checkout narrow-integration-tests-ts
2. Create a custom branch for your changes:
   • git checkout -b my-narrow-integration-tests

2. Prepare to start working

1. Open the exercise files:
   • src/node_modules/http/_http_client_test.js (or .ts)
   • src/node_modules/http/http_client.js (or .ts)
2. Run the build watcher from the root of the repository:
   • Windows: .\watch.cmd quick
   • Mac/Linux: ./watch.sh quick
3. Confirm that the build runs and ends with BUILD OK.

Exercises

The course is designed to have more exercises than you can finish in a single session, so don’t worry about finishing everything. Instead, work at your own pace and focus on understanding the material.

1. Challenge #1: Listening
2. Challenge #2: Stopping
3. Challenge #3: Requests
4. Challenge #4: Responses
5. Challenge #5: Request Data
6. Challenge #6: Response Data
7. Challenge #7: Introducing Assertions
8. Challenge #8: The Spy Server
9. Challenge #9: The Last Request
10. Challenge #10: Set the Response
11. Challenge #11: Production Code
12. Challenge #12: Happy Path
13. Bonus Challenges

Start with Challenge #1

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