public function test_crud() {

    $this->setting->default = '/* Hello World */';
    $this->assertSame( $this->setting->default, $this->setting->value() );

    $this->assertNull( wp_get_custom_css_post() );
    $this->assertNull( wp_get_custom_css_post( $this->setting->stylesheet ) );
    $this->assertNull( wp_get_custom_css_post( 'twentyten' ) );

    $original_css      = 'body { color: black; }';
    $post_id           = $this->factory()->post->create(
      array(
        'post_title'   => $this->setting->stylesheet,
        'post_name'    => $this->setting->stylesheet,
        'post_content' => $original_css,
        'post_status'  => 'publish',
        'post_type'    => 'custom_css',
      )
    );
    $twentyten_css     = 'body { color: red; }';
    $twentyten_post_id = $this->factory()->post->create(
      array(
        'post_title'   => 'twentyten',
        'post_name'    => 'twentyten',
        'post_content' => $twentyten_css,
        'post_status'  => 'publish',
        'post_type'    => 'custom_css',
      )
    );
    $twentyten_setting = new WP_Customize_Custom_CSS_Setting( $this->wp_customize, 'custom_css[twentyten]' );

    remove_theme_mod( 'custom_css_post_id' );

    $this->assertSame( $post_id, wp_get_custom_css_post()->ID );
    $this->assertSame( $post_id, wp_get_custom_css_post( $this->setting->stylesheet )->ID );
    $this->assertSame( $twentyten_post_id, wp_get_custom_css_post( 'twentyten' )->ID );

    $this->assertSame( $original_css, wp_get_custom_css( $this->setting->stylesheet ) );
    $this->assertSame( $original_css, $this->setting->value() );
    $this->assertSame( $twentyten_css, wp_get_custom_css( 'twentyten' ) );
    $this->assertSame( $twentyten_css, $twentyten_setting->value() );

    $updated_css = 'body { color: blue; }';
    $this->wp_customize->set_post_value( $this->setting->id, $updated_css );
    $saved = $this->setting->save();

    $this->assertNotFalse( $saved );
    $this->assertSame( $updated_css, $this->setting->value() );
    $this->assertSame( $updated_css, wp_get_custom_css( $this->setting->stylesheet ) );
    $this->assertSame( $updated_css, get_post( $post_id )->post_content );

    $previewed_css = 'body { color: red; }';
    $this->wp_customize->set_post_value( $this->setting->id, $previewed_css );
    $this->setting->preview();
    $this->assertSame( $previewed_css, $this->setting->value() );
    $this->assertSame( $previewed_css, wp_get_custom_css( $this->setting->stylesheet ) );

    // Make sure that wp_update_custom_css_post() works as expected for updates.
    $r = wp_update_custom_css_post(
      'body { color:red; }',
      array(
        'stylesheet'   => $this->setting->stylesheet,
        'preprocessed' => "body\n\tcolor:red;",
      )
    );
    $this->assertInstanceOf( 'WP_Post', $r );
    $this->assertSame( $post_id, $r->ID );
    $this->assertSame( 'body { color:red; }', get_post( $r )->post_content );
    $this->assertSame( "body\n\tcolor:red;", get_post( $r )->post_content_filtered );
    $r = wp_update_custom_css_post( 'body { content: "\o/"; }' );
    $this->assertSame( $this->wp_customize->get_stylesheet(), get_post( $r )->post_name );
    $this->assertSame( 'body { content: "\o/"; }', get_post( $r )->post_content );
    $this->assertSame( '', get_post( $r )->post_content_filtered );

    // Make sure that wp_update_custom_css_post() works as expected for insertion.
    $r = wp_update_custom_css_post(
      'body { background:black; }',
      array(
        'stylesheet' => 'other',
      )
    );
    $this->assertInstanceOf( 'WP_Post', $r );
    $this->assertSame( 'other', get_post( $r )->post_name );
    $this->assertSame( 'body { background:black; }', get_post( $r )->post_content );
    $this->assertSame( 'publish', get_post( $r )->post_status );

    // Test deletion.
    wp_delete_post( $post_id );
    $this->assertNull( wp_get_custom_css_post() );
    $this->assertNull( wp_get_custom_css_post( get_stylesheet() ) );
    $this->assertSame( $previewed_css, wp_get_custom_css( get_stylesheet() ), 'Previewed value remains in spite of deleted post.' );
    wp_delete_post( $twentyten_post_id );
    $this->assertNull( wp_get_custom_css_post( 'twentyten' ) );
    $this->assertSame( '', wp_get_custom_css( 'twentyten' ) );
  }