function test_custom_css_revision_saved() {
    $inserted_css = 'body { background: black; }';
    $updated_css  = 'body { background: red; }';

    $post = wp_update_custom_css_post(
      $inserted_css,
      array(
        'stylesheet' => 'testtheme',
      )
    );

    $this->assertSame( $inserted_css, $post->post_content );
    $revisions = array_values( wp_get_post_revisions( $post ) );
    $this->assertCount( 1, $revisions );
    $this->assertSame( $inserted_css, $revisions[0]->post_content );

    wp_update_custom_css_post(
      $updated_css,
      array(
        'stylesheet' => 'testtheme',
      )
    );

    $revisions = array_values( wp_get_post_revisions( $post ) );
    $this->assertCount( 2, $revisions );
    $this->assertSame( $updated_css, $revisions[0]->post_content );
    $this->assertSame( $inserted_css, $revisions[1]->post_content );
  }