diff --git a/tests/phpunit/tests/user/capabilities.php b/tests/phpunit/tests/user/capabilities.php
index b92b0db231ecb..8b99764499dd5 100644
--- a/tests/phpunit/tests/user/capabilities.php
+++ b/tests/phpunit/tests/user/capabilities.php
@@ -1406,6 +1406,7 @@ public function test_create_posts_caps() {
 		// Add 'edit_foobars' primitive cap to a user.
 		$admin->add_cap( 'edit_foobars', true );
 		$admin = new WP_User( $admin->ID );
+		self::$users['administrator'] = $admin;
 		$this->assertTrue( $admin->has_cap( $cap->create_posts ) );
 		$this->assertFalse( $author->has_cap( $cap->create_posts ) );
 		$this->assertFalse( $editor->has_cap( $cap->create_posts ) );
diff --git a/tests/phpunit/tests/user/countUserPosts.php b/tests/phpunit/tests/user/countUserPosts.php
index d7d4e1f9c8db6..05e3019799d3d 100644
--- a/tests/phpunit/tests/user/countUserPosts.php
+++ b/tests/phpunit/tests/user/countUserPosts.php
@@ -156,7 +156,12 @@ public function test_count_user_posts_for_non_existent_user() {
 	 */
 	public function test_count_user_posts_for_user_created_after_being_assigned_posts() {
 		global $wpdb;
-		$next_user_id = (int) $wpdb->get_var( "SELECT `auto_increment` FROM INFORMATION_SCHEMA.TABLES WHERE table_name = '$wpdb->users'" );
+		$next_user_id = (int) $wpdb->get_var(
+			$wpdb->prepare(
+				'SELECT AUTO_INCREMENT FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = %s',
+				$wpdb->users
+			)
+		);
 
 		// Assign post to next user.
 		self::factory()->post->create(
diff --git a/tests/phpunit/tests/user/mapMetaCap.php b/tests/phpunit/tests/user/mapMetaCap.php
index b6c6b0ab8a151..9628d89d6ee3b 100644
--- a/tests/phpunit/tests/user/mapMetaCap.php
+++ b/tests/phpunit/tests/user/mapMetaCap.php
@@ -336,22 +336,6 @@ public function test_unfiltered_html_cap() {
 		}
 	}
 
-	/**
-	 * @ticket 20488
-	 */
-	public function test_file_edit_caps_not_reliant_on_unfiltered_html_constant() {
-		$this->assertFalse( defined( 'DISALLOW_FILE_MODS' ) );
-		$this->assertFalse( defined( 'DISALLOW_FILE_EDIT' ) );
-
-		if ( ! defined( 'DISALLOW_UNFILTERED_HTML' ) ) {
-			define( 'DISALLOW_UNFILTERED_HTML', true );
-		}
-
-		$this->assertTrue( DISALLOW_UNFILTERED_HTML );
-		$this->assertSame( array( 'update_core' ), map_meta_cap( 'update_core', self::$user_id ) );
-		$this->assertSame( array( 'edit_plugins' ), map_meta_cap( 'edit_plugins', self::$user_id ) );
-	}
-
 	/**
 	 * Test a post without an author.
 	 *
@@ -458,3 +442,30 @@ public function data_meta_caps_throw_doing_it_wrong_without_required_argument_pr
 		);
 	}
 }
+
+/**
+ * @group user
+ * @group capabilities
+ * @covers ::map_meta_cap
+ */
+class Tests_User_MapMetaCap_Constants extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 20488
+	 *
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_file_edit_caps_not_reliant_on_unfiltered_html_constant() {
+		$this->assertFalse( defined( 'DISALLOW_FILE_MODS' ) );
+		$this->assertFalse( defined( 'DISALLOW_FILE_EDIT' ) );
+
+		if ( ! defined( 'DISALLOW_UNFILTERED_HTML' ) ) {
+			define( 'DISALLOW_UNFILTERED_HTML', true );
+		}
+
+		$this->assertTrue( DISALLOW_UNFILTERED_HTML );
+		$this->assertSame( array( 'update_core' ), map_meta_cap( 'update_core', 0 ) );
+		$this->assertSame( array( 'edit_plugins' ), map_meta_cap( 'edit_plugins', 0 ) );
+	}
+}
diff --git a/tests/phpunit/tests/user/query.php b/tests/phpunit/tests/user/query.php
index 5978f4bf55e58..da855fc9e22c4 100644
--- a/tests/phpunit/tests/user/query.php
+++ b/tests/phpunit/tests/user/query.php
@@ -1656,20 +1656,20 @@ public function test_calling_prepare_query_a_second_time_should_not_add_another_
 	 */
 	public function test_search_by_display_name_only() {
 
-		$new_user1          = self::factory()->user->create(
+		$new_user1 = self::factory()->user->create(
 			array(
 				'user_login'   => 'name1',
 				'display_name' => 'Sophia Andresen',
 			)
 		);
-		self::$author_ids[] = $new_user1;
+		$author_ids = array_merge( self::$author_ids, array( $new_user1 ) );
 
 		$q = new WP_User_Query(
 			array(
 				'search'         => '*Sophia*',
 				'fields'         => '',
 				'search_columns' => array( 'display_name' ),
-				'include'        => self::$author_ids,
+				'include'        => $author_ids,
 			)
 		);
 
@@ -1684,20 +1684,20 @@ public function test_search_by_display_name_only() {
 	 */
 	public function test_search_by_display_name_only_ignore_others() {
 
-		$new_user1          = self::factory()->user->create(
+		$new_user1 = self::factory()->user->create(
 			array(
 				'user_login'   => 'Sophia Andresen',
 				'display_name' => 'name1',
 			)
 		);
-		self::$author_ids[] = $new_user1;
+		$author_ids = array_merge( self::$author_ids, array( $new_user1 ) );
 
 		$q = new WP_User_Query(
 			array(
 				'search'         => '*Sophia*',
 				'fields'         => '',
 				'search_columns' => array( 'display_name' ),
-				'include'        => self::$author_ids,
+				'include'        => $author_ids,
 			)
 		);