A test that repeats the implementation can pass while proving very little. If the production code calculates a value and the test copies the same calculation to find the expected value, both can make the same mistake quite happily. I want the test to have a reason to disagree.<\/p>\n
For me, that starts with the behaviour somebody depends on. Give it a concrete input and an expected outcome that follows from the requirement. If a bug involved the end of a date range, a repeated request or a missing record, keep that example. It explains why the test exists and gives a future change something meaningful to preserve.<\/p>\n
That does not mean every line needs an elaborate test harness. Some changes are better checked by inspecting a render, running an existing integration check or verifying a real output. Building an abstraction purely so a trivial assignment can be tested often adds more code to maintain than the change itself. The check should fit the risk and the uncertainty.<\/p>\n
I would rather review a small set of tests with clear failure meanings than a large set that mostly asserts its own setup. A useful failure says which promise broke. A green result should give us a specific reason to trust the behaviour, rather than just another number for a coverage report.<\/p>\n","protected":false},"excerpt":{"rendered":"
A test that repeats the implementation can pass while proving very little.<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[25],"tags":[118,276,181],"class_list":["post-1442","post","type-post","status-publish","format-standard","hentry","category-software-engineer","tag-code-review","tag-software-quality","tag-testing"],"yoast_head":"\n