fix(helper): fix test since webpack 4 changes

since `webpack.optimize.CommonsChunkPlugin`
was removed it recommend
`config.optimization.splitChunks` instead

Author: DrSensor

package.json

@@ -41,7 +41,7 @@
     "index.js"
   ],
   "peerDependencies": {
-    "webpack": "^4.3.0"
+    "webpack": "^4.12.0"
   },
   "dependencies": {
     "@webpack-contrib/schema-utils": "^1.0.0-beta.0",

test/helpers/compiler.js

@@ -22,13 +22,7 @@ const modules = (config) => {
   };
 };
 
-const plugins = (config) =>
-  [
-    new webpack.optimize.CommonsChunkPlugin({
-      names: ['runtime'],
-      minChunks: Infinity,
-    }),
-  ].concat(config.plugins || []);
+const plugins = (config) => [].concat(config.plugins || []);
 
 const output = (config) => {
   return {

test/loader.test.js

@@ -10,7 +10,7 @@ describe('Loader', () => {
     };
 
     const stats = await webpack('fixture.js', config);
-    const { source } = stats.toJson().modules[1];
+    const [{ source }] = stats.toJson().modules;
 
     expect(source).toMatchSnapshot();
   });

test/options.test.js

@@ -11,7 +11,7 @@ describe('Options', () => {
       };
 
       const stats = await webpack('fixture.js', config);
-      const { source } = stats.toJson().modules[1];
+      const [{ source }] = stats.toJson().modules;
 
       expect(source).toMatchSnapshot();
     });