Expectations #

Pest provides a fantastic expectation API that you can use in place of the more traditional ->assert... methods. In vanilla Pest projects they look like this,

expect($something)->toBe($somethingElse);

When you call expect() it returns an "expectable object" that you can chain your expectations on to. The most common expectation is ->toBe() and it checks that the thing your "expecting" is the same as the thing it should "be."

In Craft you could expect that a response is 200 Ok like this,

expect($response)->statusCode->toBe(200);

You can also chain multiple expectations and each one will execute in order. For example, we could check the statusCode as well as the contentType to ensure we're getting back HTML.

expect($response)
    ->statusCode->toBe(200)
    ->contentType->toBe('text/html');

It's important to note that each time you call an expectation's ->to... method the chain resets back to the original expectation. Here's a slightly more contrived example to illustrate that,

expect($person)
    ->firstName->toBe('Michael')
    ->lastName->toBe('Bluth')
    ->brothers->toHaveCount(2)
    ->brothers[0]->firstName->toBe('Gob')
    ->father->firstName->toBe('George')
    ->mother->firstName->toBe('Lucille');

Note the nesting above, even though we're calling $person->brothers[0]->firstName, after we call ->toBe() the chain is reset and the next expectation reverts back to the original $person.

You can use this feature to start an expectation on a response and from there assert several values and DOM nodes all at the same time. For example,

expect($response)
    ->statusCode->toBe(200)
    ->querySelector('h1')->text->toBe('Hello World!')
    ->querySelector('.news__item')->count->toBe(5)
    ->querySelector('.person__name')->text->toBe(['Michael', 'Gob']);