added unit test for isImageUrl

packages/block-editor/src/components/link-control/is-url-image.js

@@ -4,6 +4,7 @@
  * @return {boolean} true if the url is an image url.
  */
 export default function isImageUrl( url ) {
-	const pattern = /(http(s?):)([/|.|\w|\s|-])*\.(?:jpg|gif|png)/g;
+	const pattern =
+		/^(https?:\/\/)([\w-]+(?:\.[\w-]+)*\/)*[\w-]+\.(?:jpg|JPG|jpeg|gif|png|webp)$/i;
 	return pattern.test( url );
 }

packages/block-editor/src/components/link-control/test/is-url-image.js

@@ -0,0 +1,28 @@
+/**
+ * Internal dependencies
+ */
+import isImageUrl from '../is-url-image';
+
+describe( 'isImageUrl', () => {
+	// use .each to test multiple cases
+	it.each( [
+		[ true, 'https://example.com/image.jpg' ],
+		[ true, 'https://example.com/image.gif' ],
+		[ true, 'https://example.com/image.png' ],
+		[ true, 'https://example.com/image.webp' ],
+		[ true, 'https://example.com/image.jpeg' ],
+		[ true, 'https://example.com/image.JPG' ],
+		[ false, 'https://example.com/image.txt' ],
+		[ false, 'https://example.com/image' ],
+		[ false, 'https://example.com/image.jpg?query=123' ],
+		[ false, '' ],
+		[ false, null ],
+		[ false, undefined ],
+		[ false, 123 ],
+	] )(
+		'returns %s when testing against URL "%s" for a valid image',
+		( expected, testString ) => {
+			expect( isImageUrl( testString ) ).toBe( expected );
+		}
+	);
+} );