diff --git a/tests/phpunit/tests/widgets/wpWidgetRss.php b/tests/phpunit/tests/widgets/wpWidgetRss.php
new file mode 100644
index 0000000000..65318423ff
--- /dev/null
+++ b/tests/phpunit/tests/widgets/wpWidgetRss.php
@@ -0,0 +1,119 @@
+<?php
+/**
+ * Unit tests covering WP_Widget_RSS functionality.
+ *
+ * @package    WordPress
+ * @subpackage widgets
+ */
+
+/**
+ * Test wp-includes/widgets/class-wp-widget-rss.php
+ *
+ * @group widgets
+ */
+class Test_Widgets_wpWidgetRss extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 53278
+	 * @covers WP_Widget_RSS::widget
+	 * @dataProvider data_url_unhappy_path
+	 *
+	 * @param mixed $url When null, unsets 'url' arg, else, sets to given value.
+	 */
+	public function test_url_unhappy_path( $url ) {
+		$widget   = new WP_Widget_RSS();
+		$args     = array(
+			'before_title'  => '<h2>',
+			'after_title'   => "</h2>\n",
+			'before_widget' => '<section id="widget_rss-5" class="widget widget_rss">',
+			'after_widget'  => "</section>\n",
+		);
+		$instance = array(
+			'title' => 'Foo',
+			'url'   => $url,
+		);
+
+		if ( is_null( $url ) ) {
+			unset( $instance['ur'] );
+		}
+
+		$this->expectOutputString( '' );
+
+		$widget->widget( $args, $instance );
+	}
+
+	public function data_url_unhappy_path() {
+		return array(
+			'when unset'         => array(
+				'url' => null,
+			),
+			'when empty string'  => array(
+				'url' => '',
+			),
+			'when boolean false' => array(
+				'url' => false,
+			),
+		);
+	}
+
+	/**
+	 * @ticket 53278
+	 * @covers WP_Widget_RSS::widget
+	 * @dataProvider data_url_happy_path
+	 *
+	 * @param mixed  $url      URL argument.
+	 * @param string $expected Expected output.
+	 */
+	public function test_url_happy_path( $url, $expected ) {
+		add_filter( 'pre_http_request', array( $this, 'mocked_rss_response' ) );
+
+		$widget   = new WP_Widget_RSS();
+		$args     = array(
+			'before_title'  => '<h2>',
+			'after_title'   => "</h2>\n",
+			'before_widget' => '<section id="widget_rss-5" class="widget widget_rss">',
+			'after_widget'  => "</section>\n",
+		);
+		$instance = array(
+			'title' => 'Foo',
+			'url'   => $url,
+		);
+
+		if ( is_null( $url ) ) {
+			unset( $instance['ur'] );
+		}
+
+		ob_start();
+		$widget->widget( $args, $instance );
+		$actual = ob_get_clean();
+
+		$this->assertContains( $expected, $actual );
+	}
+
+	public function data_url_happy_path() {
+		return array(
+			'when url is given' => array(
+				'url' => 'https://wordpress.org/news/feed/',
+				'<section id="widget_rss-5" class="widget widget_rss"><h2><a class="rsswidget" href="https://wordpress.org/news/feed/">',
+			),
+		);
+	}
+
+	public function mocked_rss_response() {
+		$single_value_headers = array(
+			'content-type' => 'application/rss+xml; charset=UTF-8',
+			'link'         => '<https://wordpress.org/news/wp-json/>; rel="https://api.w.org/"',
+		);
+
+		return array(
+			'headers'  => new Requests_Utility_CaseInsensitiveDictionary( $single_value_headers ),
+			'body'     => file_get_contents( DIR_TESTDATA . '/feed/wordpress-org-news.xml' ),
+			'response' => array(
+				'code'    => 200,
+				'message' => 'OK',
+			),
+			'cookies'  => array(),
+			'filename' => null,
+		);
+	}
+}