testing – Page 24 – Türker Yıldırım

Bootstrap 5 removed jQuery and found what depended on it

Deep diveMay 5, 202110 min read

A CSS framework upgrade that turned out to be a JavaScript audit. The modals work and four things around them do not.

An index that made writes slower than the reads it saved

Deep diveApril 23, 202110 min read

Eleven indexes on a table with a heavy write path. Every index is a write amplification that nobody measured, and three of them were never used.

Fault injection: timeout, 500, and a slow trickle

NoteApril 21, 20211 min read

Every test mocks a fast success, and every production incident is one of the four failure modes nobody wrote a test for. The slow trickle is the one…

Contract tests against the provider’s own document

NoteApril 21, 20211 min read

A mock is your belief about the provider, and a contract test compares that belief with their published schema. Running it on a schedule rather than on every…

Octane keeps the application in memory and finds every static you left

Deep diveApril 21, 202110 min read

40ms becomes 8ms, and the fourth request returns another customer’s data. The shared-nothing assumption is load-bearing in more places than anybody had counted.

Visual regression needs a stable font stack

NoteApril 13, 20212 min read

A screenshot comparison fails on a one-pixel difference, and font rendering differs between a laptop and a CI runner. Running the browser in a pinned container is the…

Wait for a compose service to be healthy before running tests

SnippetApril 12, 20211 min read

The staging environment that was lying

Deep diveApril 8, 202110 min read

It passed on staging four times and failed in production four times. The same code, a different outcome, and five differences nobody had enumerated.

A WordPress plugin with a test suite that runs in CI

Deep diveMarch 18, 202110 min read

A plugin on forty sites and no test that was not a person clicking. WordPress is a global, and the matrix is the actual value.

Mutation testing finds the test that asserts nothing

NoteMarch 10, 20212 min read

Line coverage says a line ran, and mutation testing says a test would have noticed if it were wrong. The forty-three are the interesting number and they are…