Mocking WordPress Objects

Mocking calls to wpdb, WP_Query, etc. can be done using the Mockery framework. While this isn't part of WP Mock itself, complex code will often need these objects and this framework will let you incorporate those into your tests. Since WP Mock requires Mockery, it should already be included as part of your installation.

An example with WPDB

Let's say we have a function that gets three post IDs from the database.

namespace MyPlugin;

class MyClass
{
    public function getSomePostIds() : array 
    {
        global $wpdb;
        return $wpdb->get_col("SELECT ID FROM {$wpdb->posts} LIMIT 3");
    }
}

When we mock the $wpdb object, we're not performing an actual database call, only mocking the results. We need to call the get_col method with an SQL statement, and return three arbitrary post IDs.

use Mockery;
use MyPlugin\MyClass;

final class MyClassTest extends \WP_Mock\Tools\TestCase
{
    public function testCanGetSomePostIds() : void
    {
        global $wpdb;

        $wpdb = Mockery::mock('WPDB');
        $wpdb->posts = 'wp_posts';

        $wpdb->allows('get_col')
            ->once()
            ->with('SELECT ID FROM wp_posts LIMIT 3')
            ->andReturn([1, 2, 3]);

        $postIds = (new MyClass())->getSomePostIds();

        $this->assertEquals([1, 2, 3], $postIds);
    }
}