diff --git a/tests/phpunit/tests/rest-api/rest-categories-controller.php b/tests/phpunit/tests/rest-api/rest-categories-controller.php
index 01bddd3738..ef72b6f8fa 100644
--- a/tests/phpunit/tests/rest-api/rest-categories-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-categories-controller.php
@@ -38,7 +38,7 @@ class WP_Test_REST_Categories_Controller extends WP_Test_REST_Controller_Testcas
 
 		// Set up categories for pagination tests.
 		for ( $i = 0; $i < self::$total_categories - 1; $i++ ) {
-			$category_ids[] = $factory->category->create(
+			self::$category_ids[] = $factory->category->create(
 				array(
 					'name' => "Category {$i}",
 				)
diff --git a/tests/phpunit/tests/rest-api/rest-comments-controller.php b/tests/phpunit/tests/rest-api/rest-comments-controller.php
index 99986a8037..bf5d112d4e 100644
--- a/tests/phpunit/tests/rest-api/rest-comments-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-comments-controller.php
@@ -117,7 +117,7 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 
 		// Set up comments for pagination tests.
 		for ( $i = 0; $i < self::$total_comments - 1; $i++ ) {
-			$comment_ids[] = $factory->comment->create(
+			self::$comment_ids[] = $factory->comment->create(
 				array(
 					'comment_content' => "Comment {$i}",
 					'comment_post_ID' => self::$post_id,
diff --git a/tests/phpunit/tests/rest-api/rest-tags-controller.php b/tests/phpunit/tests/rest-api/rest-tags-controller.php
index b9ac20cf71..788d6901f2 100644
--- a/tests/phpunit/tests/rest-api/rest-tags-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-tags-controller.php
@@ -54,7 +54,7 @@ class WP_Test_REST_Tags_Controller extends WP_Test_REST_Controller_Testcase {
 
 		// Set up tags for pagination tests.
 		for ( $i = 0; $i < self::$total_tags; $i++ ) {
-			$tag_ids[] = $factory->tag->create(
+			self::$tag_ids[] = $factory->tag->create(
 				array(
 					'name' => "Tag {$i}",
 				)
@@ -412,6 +412,8 @@ class WP_Test_REST_Tags_Controller extends WP_Test_REST_Controller_Testcase {
 		$response = rest_get_server()->dispatch( $request );
 		$tags     = $response->get_data();
 
+		$this->assertNotEmpty( $tags );
+
 		$i = 0;
 		foreach ( $tags as $tag ) {
 			$this->assertSame( $tag['name'], "Tag {$i}" );
@@ -426,6 +428,8 @@ class WP_Test_REST_Tags_Controller extends WP_Test_REST_Controller_Testcase {
 		$response = rest_get_server()->dispatch( $request );
 		$tags     = $response->get_data();
 
+		$this->assertNotEmpty( $tags );
+
 		foreach ( $tags as $tag ) {
 			$this->assertSame( $tag['name'], "Tag {$i}" );
 			$i++;