4_test_fetchArticles.md

Jest Test for fetchArticles Function

Overview:

This test suite checks if the function fetches articles from Firestore. It covers scenarios where an issueTimestamp is provided and when it is not.

Test Setup:

1. Mocked Firebase: The test uses a fake Firebase setup, as outlined in design note: 5_fake_firebase.md

2. Fixture Data: Fixture data, resembling actual Firestore responses, is utilized for both the latest and older issues and their associated articles. (spec/fixtures)

Test Cases:

1. Without issueTimestamp:

   • Setup: Mocked Firestore functions simulate fetching the latest issue and its articles.
   • Expectations: Verifies that the function correctly initializes Firebase, constructs the Firestore query, and transforms the fetched data.

2. With issueTimestamp:

   • Setup: Simulates fetching an older issue and its articles using a provided issueTimestamp.
   • Expectations: Checks that the function handles the timestamp filtering correctly, ensuring the retrieval of the next issue's articles.