MySQL UTF-8 4 Bytes character problem

gistfile1.php

<?php

class SampleTest extends WP_UnitTestCase {

	/**
	 * @test
	 */
	function utf8_test()
	{
		global $wp_version;
		global $wpdb;

		$this->assertSame( '4.2', $wp_version );

		// post_title is sushi
		$post_id = $this->factory->post->create( array( 'post_title' => '🍣' ) );

		// search by beer
		$result = $wpdb->get_var( $wpdb->prepare( 
			"SELECT ID FROM $wpdb->posts where post_title=%s", '🍺'
		) );

		// It should be null but 3
		$this->assertSame( NULL, $result ); // fail
	}


}