This may or may not be specific to Laravel. Although a Laravel helper is involved, this issue may occur elsewhere.
assertJsonCount utilises the PHPUnit function PHPUnit::assertCount which uses a laravel helper data_get, which has the following signature:
/**
* Get an item from an array or object using "dot" notation.
*
* @param mixed $target
* @param string|array|int $key
* @param mixed $default
* @return mixed
*/
function data_get($target, $key, $default = null)
{
if (is_null($key)) {
return $target;
}
...
We can see that the JSON returned is a nested array, so logically we should pass in a key of 0.
$response->assertJsonCount($expectedProducts->count(), '0');
However this will be ignored as assertCount function checks if a key has been passed using is_null.
To overcome this, we can count all children of 0:
$response->assertJsonCount($expectedProducts->count(), '0.*');
This will produce the desired result.