add functional test for svelte

Author: zairigimad

fixtures/js/hello_world.svelte

@@ -0,0 +1,5 @@
+<script>
+	let name = 'world';
+</script>
+
+<h1>Hello {name}!</h1>

lib/config-generator.js

@@ -394,8 +394,6 @@ class ConfigGenerator {
         }
 
         if (this.webpackConfig.useSvelte) {
-            loaderFeatures.ensurePackagesExistAndAreCorrectVersion('svelte');
-
             rules.push(applyRuleConfigurationCallback('svelte', {
                 resolve: {
                     mainFields: ['svelte', 'browser', 'module', 'main'],

test/functional.js

@@ -1330,6 +1330,23 @@ module.exports = {
             });
         });
 
+        it('When enabled, svelte is transformed', (done) => {
+            const config = createWebpackConfig('www/build', 'dev');
+            config.setPublicPath('/build');
+            config.addEntry('main', './js/hello_world.svelte');
+            config.enableSvelte();
+
+            testSetup.runWebpack(config, (webpackAssert) => {
+                // check that babel transformed the svelte files
+                webpackAssert.assertOutputFileContains(
+                    'main.js',
+                    'SvelteComponent'
+                );
+
+                done();
+            });
+        });
+
         it('When enabled, preact JSX is transformed with preact-compat!', (done) => {
             const config = createWebpackConfig('www/build', 'dev');
             config.setPublicPath('/build');