Tests: Use assertSame() in new_admin_email_subject filter test.

This ensures that not only the return values match the expected results, but also that their type is the same.

Going forward, stricter type checking by using `assertSame()` should generally be preferred to `assertEquals()` where appropriate, to make the tests more reliable.

Follow-up to [57283].

See #59655.

git-svn-id: https://develop.svn.wordpress.org/trunk@57706 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

tests/phpunit/tests/admin/includesMisc.php

@@ -32,12 +32,12 @@ public function test_shorten_url() {
 	 * @ticket 59520
 	 */
 	public function test_new_admin_email_subject_filter() {
-		// Default value
+		// Default value.
 		$mailer = tests_retrieve_phpmailer_instance();
 		update_option_new_admin_email( 'old@example.com', 'new@example.com' );
-		$this->assertEquals( '[Test Blog] New Admin Email Address', $mailer->get_sent()->subject );
+		$this->assertSame( '[Test Blog] New Admin Email Address', $mailer->get_sent()->subject );
 
-		// Filtered value
+		// Filtered value.
 		add_filter(
 			'new_admin_email_subject',
 			function () {
@@ -51,6 +51,6 @@ function () {
 
 		$mailer = tests_retrieve_phpmailer_instance();
 		update_option_new_admin_email( 'old@example.com', 'new@example.com' );
-		$this->assertEquals( 'Filtered Admin Email Address', $mailer->get_sent()->subject );
+		$this->assertSame( 'Filtered Admin Email Address', $mailer->get_sent()->subject );
 	}
 }