Question

I have recently started to write unit tests in my projects and I notice that all assert statements have a message argument.

What makes a good message for a unit test?

$cache->set('foo', 3);
$this->assertEquals($cache->get('foo'), 3, 'what should i say?');

Thanks!

Answer 1

State the fact under test.

Consider:

$this->assertEquals($person->age, 21, "Age is 21")

vs.:

$this->assertEquals($person->age, 21, "Age of person born on 1990-12-20");

A good unit test message should help you quickly guess where the bug is. A bad one makes you spend more time hunting.