integration-testing – Page 4 – Türker Yıldırım

The service we merged back

Deep diveFebruary 15, 202414 min read

Two services extracted in 2021, a team of four maintaining four pipelines, and forty-one of forty-four releases touching both.

A fixture builder instead of a fixture file

NoteDecember 19, 20231 min read

A JSON fixture of a full order, loaded by 40 tests, where each test cared about two fields and was coupled to the other thirty. The fixture file…

The test that failed only when run alone

NoteNovember 21, 20232 min read

The usual failure is a test that passes alone and fails in the suite; this was the reverse, and the reverse is more interesting. A test that depends…

The interface with one implementation, and when that is fine

Deep diveNovember 16, 202310 min read

140 interfaces, 128 of them with exactly one implementation, and a jump-to-definition that always lands on the wrong file.

A snapshot test for an email, and the day it caught something

NoteNovember 13, 20232 min read

Snapshot tests are usually a way of asserting that nothing changed, which is worth very little, until the change is one nobody intended. The snapshot caught a currency…

Mutation testing for one directory, and what it found

Deep diveOctober 24, 202310 min read

94% line coverage on the pricing code, and a bug that shipped anyway. A test that called the method and asserted it did not throw.

An outbox, and the publisher we removed from the transaction

Deep diveSeptember 20, 202310 min read

An order committed and an event never published, twice in one week. A broker call inside a database transaction, and a rollback after it.

Testing a queue by asserting the payload, not the effect

NoteSeptember 20, 20232 min read

A test that dispatched a job and then asserted on the database is testing two things and failing for two reasons. Splitting at the queue boundary is the…

A suite that runs in four minutes because it stopped touching the database

Deep diveMay 28, 202310 min read

1,400 tests, fourteen minutes, and 1,100 of them opening a transaction against MySQL for no reason anybody could name.

The anti-corruption layer we should have written first

Deep diveMay 9, 202310 min read

A supplier who renamed four fields in a minor release, without notice, and twenty-two files touched to accommodate it.