diff --git a/tests/phpunit/tests/rest-api/rest-posts-controller.php b/tests/phpunit/tests/rest-api/rest-posts-controller.php
index 26af946..0c043dd 100644
--- a/tests/phpunit/tests/rest-api/rest-posts-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-posts-controller.php
@@ -1608,6 +1608,22 @@ class WP_Test_REST_Posts_Controller extends WP_Test_REST_Post_Type_Controller_Te
 		$this->assertEquals( $params['excerpt'], $post->post_excerpt );
 	}
 
+	public function test_update_item_no_change() {
+		wp_set_current_user( self::$editor_id );
+		$post = get_post( self::$post_id );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/posts/%d', self::$post_id ) );
+		$request->set_param( 'author', $post->post_author );
+
+		// Run twice to make sure that the update still succeeds even if no DB
+		// rows are updated.
+		$response = $this->server->dispatch( $request );
+		$this->check_update_post_response( $response );
+
+		$response = $this->server->dispatch( $request );
+		$this->check_update_post_response( $response );
+	}
+
 	public function test_rest_update_post() {
 		wp_set_current_user( self::$editor_id );
 
diff --git a/tests/phpunit/tests/rest-api/rest-tags-controller.php b/tests/phpunit/tests/rest-api/rest-tags-controller.php
index 4c461d3..bdca9cb 100644
--- a/tests/phpunit/tests/rest-api/rest-tags-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-tags-controller.php
@@ -554,6 +554,25 @@ class WP_Test_REST_Tags_Controller extends WP_Test_REST_Controller_Testcase {
 		$this->assertEquals( 'new-slug', $data['slug'] );
 	}
 
+	public function test_update_item_no_change() {
+		wp_set_current_user( self::$administrator );
+		$term = get_term_by( 'id', $this->factory->tag->create(), 'post_tag' );
+
+		$request = new WP_REST_Request( 'PUT', '/wp/v2/tags/' . $term->term_id );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$request->set_param( 'slug', $term->slug );
+
+		// Run twice to make sure that the update still succeeds even if no DB
+		// rows are updated.
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
 	public function test_update_item_invalid_term() {
 		wp_set_current_user( self::$administrator );
 		$request = new WP_REST_Request( 'POST', '/wp/v2/tags/' . REST_TESTS_IMPOSSIBLY_HIGH_NUMBER );
diff --git a/tests/phpunit/tests/rest-api/rest-users-controller.php b/tests/phpunit/tests/rest-api/rest-users-controller.php
index 8da864f..62da922 100644
--- a/tests/phpunit/tests/rest-api/rest-users-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-users-controller.php
@@ -1087,6 +1087,23 @@ class WP_Test_REST_Users_Controller extends WP_Test_REST_Controller_Testcase {
 		$this->assertEquals( $pw_before, $user->user_pass );
 	}
 
+	public function test_update_item_no_change() {
+		$this->allow_user_to_manage_multisite();
+		wp_set_current_user( self::$user );
+		$user = get_userdata( self::$editor );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/users/%d', self::$editor ) );
+		$request->set_param( 'slug', $user->user_nicename );
+
+		// Run twice to make sure that the update still succeeds even if no DB
+		// rows are updated.
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
 	public function test_update_item_existing_email() {
 		$user1 = $this->factory->user->create( array( 'user_login' => 'test_json_user', 'user_email' => 'testjson@example.com' ) );
 		$user2 = $this->factory->user->create( array( 'user_login' => 'test_json_user2', 'user_email' => 'testjson2@example.com' ) );