I recently heard this interesting question: if your project uses a static analysis tool like PHPStan or Psalm (as it should), should the tests by analysed too?

The first thing to consider: what are potential reasons for not analysing your test code?

Why not?

1. Tests are messy in terms of types

Tests may use mocks, which can be confusing for the static analyser:

$object = $this->createMock(MockedInterface::class);

The actual type of $object is an intersection type, i.e. $object is both a MockObject and a MockedInterface, but the analyser only recognizes MockObject. You may not like all those warnings about “unknown method” calls on MockObject $object so you exclude test code from the analysis.