The Life Starter
0 of 6 complete0%
Course Library · Lesson 6 of 6
Digital · Guided lesson

Test a complete response matrix

About 31 minutes · 6 reading + 25 practice and checks
Time includes reading, practice, and questions. Extra videos or further study are optional.
See this course’s project requirements

A tested local API-response viewer with a request contract, validation rules, six response cases and an honest integration handoff.

Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.

What to include

  • Request/response contract with limits.
  • Type and status observations.
  • Working local viewer.
  • Explicit empty/error/validation behavior.
  • Six-case test matrix and README.

Review and revise

Use these criteria to check your work and choose what to improve.

  • Fields and types are understood.
  • Failures do not show stale results.
  • All six cases behave as described.
  • Simulation and live-integration limits are explicit.
Open the full course project
Want more background?
Before you begin

The idea in everyday life

Build a read-only viewer for a fictional library-hours API contract.

The idea

A response matrix tests categories of behavior, not just one happy example.

Follow along

Test a complete response matrix — guided practice

Demonstrate accepted, empty, malformed and error cases in a repeatable handoff.

Save api-viewer.html from the download and open it in a modern browser. Open its source in a text editor. The complete original file supplies every fixture and function. It simulates GET /hours locally; it does not contact a real library. Reload after edits; restore the supplied file before each lesson unless told otherwise.

  1. 1. Restore the original

    Replace any experimental changes with the supplied api-viewer.html.

    You should see: The initial two branch durations are 8 and 5.

    A known starting state makes the test record reproducible.

  2. 2. Run six cases

    Run success, empty, missing, wrong-type, server-error and malformed in that order.

    You should see: Only success has two list items; empty is valid with zero; four cases report errors.

    Each case probes a different response assumption.

  3. 3. Record exact evidence

    Use test-log.md to record case, status/list count and whether the button can run again.

    You should see: All six cases leave the button enabled after completion.

    Recovery is part of correct behavior.

  4. 4. Package

    Save viewer, test log and a README saying local simulation, schema, limitations and optional live-integration requirements.

    You should see: Another learner can reproduce the cases without an account.

    The handoff distinguishes demonstrated logic from untested transport.

Now change one thing

A test matrix includes 3 accepted and 5 rejected cases. How many cases must the log contain?

Your work

What to finish

A tested local API viewer, contract note and response matrix.

Common mistake

Watch for this

Counting a simulated test as evidence of live API integration.

How can I tell I understand it?

Complete the changed case, explain your result, and pass the three application checks.

Try 3 questions

Quick knowledge check

Answer all 3 questions. Get at least 2 right and the lesson completes automatically.

Not yet passed

You’ll get an explanation for each answer. Signed in? Your results save to your account.

1A viewer is tested only with nonempty success. Which missing case could expose stale results?
2Two of seven planned cases were never run. How many may be reported as tested?
3Which handoff claim accurately describes this project?
0 of 3 answeredApply the lesson to a short question, then review the explanation.
6
Finish this lesson

Pass the check. We’ll save the progress.

Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.

Go to the knowledge check
Optional course overview video · same video as Lesson 1
freeCodeCamp.orgAPIs for Beginners - How to use an API (Full Course / Tutorial)YouTube
Optional course overview

APIs for Beginners - How to use an API (Full Course / Tutorial)

From freeCodeCamp.org. Watch here or open it on YouTube .

Optional course overview. Follow the written steps below at your own pace.
Tools, templates, and lesson sources

Tools and templates

Tools open in a new tab so you can keep your place here.

Sources and further reading

Explore the references behind this lesson.

MDN: Working with JSON
Source & access notes · checked 2026-09-12

Opened and inspected on 2026-09-12: JSON types and parsing.

Access: Free public web page; no paid enrollment required.

Reuse: Public reference; link only. LifeStarter prose, exercises and files are independently authored.

MDN: Using the Fetch API
Source & access notes · checked 2026-09-12

Opened and inspected on 2026-09-12: Responses, promises and explicit HTTP status checks.

Access: Free public web page; no paid enrollment required.

Reuse: Public reference; link only. LifeStarter prose, exercises and files are independently authored.

MDN: HTTP response status codes
Source & access notes · checked 2026-09-12

Opened and inspected on 2026-09-12: 200, 404 and server-error categories.

Access: Free public web page; no paid enrollment required.

Reuse: Public reference; link only. LifeStarter prose, exercises and files are independently authored.

Report a problem with this lesson

Tell us what went wrong. Please leave out personal information and private project contents.

No sign-in needed.