Improve test cases.

test/urlExtension.test.js

@@ -3,9 +3,10 @@ import { getUrlExtension } from '../src/utilities/urlExtension.js';
 describe( 'getUrlExtension', () => {
 
 	it.each( [
-		'https://nasa.gov/foo/bar/baz.qux/tileset.json',
-		'https://nasa.gov/foo/bar/baz.qux/tileset.json?foo=bar',
-		'https://nasa.gov/foo/bar/baz.qux/tileset.json?a.b=c.d',
+		'https://nasa.gov/foo/bar.baz/tileset.json',
+		'https://nasa.gov/foo/bar.baz/tileset.json?foo=bar',
+		'https://nasa.gov/foo/bar.baz/tileset.json?a.b=c.d',
+		'https://nasa.gov/foo/bar.baz/tileset.json?a.b=c.d#e.f',
 		'https://nasa.gov/tileset.json',
 		'https://nasa.gov//tileset.json',
 		'file:///Users/JaneScientist/code/3DTilesRendererJS/example/b3dmExample.json',
@@ -14,7 +15,8 @@ describe( 'getUrlExtension', () => {
 		'foo.json?a=b',
 		'/foo.json',
 		'/foo/bar.json',
-	] )( 'parses the json extension out of %s', url => {
+		'png.svg.json'
+	] )( 'parses extensions (%s)', url => {
 
 		expect( getUrlExtension( url ) ).toBe( 'json' );
 
@@ -24,12 +26,16 @@ describe( 'getUrlExtension', () => {
 		'https://nasa.gov',
 		'https://nasa.gov/',
 		'https://nasa.gov/tileset',
-		'https://nasa.gov/foo/bar/baz.qux/tileset?foo=bar',
-		'https://nasa.gov/foo/bar/baz.qux/tileset?a.b=c.d',
+		'https://nasa.gov/foo/bar.baz/tileset?foo=bar',
+		'https://nasa.gov/foo/bar.baz/tileset?a.b=c.d',
 		'https://nasa.gov/tileset',
 		'https://nasa.gov/tileset.',
 		'Pleiades',
-	] )( 'returns null for strings that are not URLs with extensions %s', url => {
+		'.',
+		'..',
+		'',
+		undefined,
+	] )( 'returns null for values that are not URLs with extensions (%s)', url => {
 
 		expect( getUrlExtension( url ) ).toBeNull();