Add new test case for project with CSS modules

Author: jsnajdr

packages/dependency-extraction-webpack-plugin/test/__snapshots__/build.js.snap

@@ -244,6 +244,29 @@ Array [
 ]
 `;
 
+exports[`DependencyExtractionWebpackPlugin Webpack \`style-imports\` should produce expected output: Asset file 'main.asset.php' should match snapshot 1`] = `
+"<?php return array('dependencies' => array('lodash', 'wp-blob'), 'version' => '87d097ece7eeb99faa63');
+"
+`;
+
+exports[`DependencyExtractionWebpackPlugin Webpack \`style-imports\` should produce expected output: External modules should match snapshot 1`] = `
+Array [
+  Object {
+    "externalType": "window",
+    "request": "lodash",
+    "userRequest": "lodash",
+  },
+  Object {
+    "externalType": "window",
+    "request": Array [
+      "wp",
+      "blob",
+    ],
+    "userRequest": "@wordpress/blob",
+  },
+]
+`;
+
 exports[`DependencyExtractionWebpackPlugin Webpack \`wordpress\` should produce expected output: Asset file 'main.asset.php' should match snapshot 1`] = `
 "<?php return array('dependencies' => array('lodash', 'wp-blob'), 'version' => '4c78134607e6ed966df3');
 "

packages/dependency-extraction-webpack-plugin/test/fixtures/style-imports/index.js

@@ -0,0 +1,16 @@
+/**
+ * WordPress dependencies
+ */
+import { isBlobURL } from '@wordpress/blob';
+
+/**
+ * External dependencies
+ */
+import _ from 'lodash';
+
+/**
+ * Internal dependencies
+ */
+import './style.css';
+
+_.isEmpty( isBlobURL( '' ) );

packages/dependency-extraction-webpack-plugin/test/fixtures/style-imports/style.css

@@ -0,0 +1 @@
+body { color: white; }

packages/dependency-extraction-webpack-plugin/test/fixtures/style-imports/webpack.config.js

@@ -0,0 +1,31 @@
+/**
+ * External dependencies
+ */
+const MiniCSSExtractPlugin = require( 'mini-css-extract-plugin' );
+
+/**
+ * Internal dependencies
+ */
+const DependencyExtractionWebpackPlugin = require( '../../..' );
+
+module.exports = {
+	plugins: [
+		new DependencyExtractionWebpackPlugin(),
+		new MiniCSSExtractPlugin(),
+	],
+	module: {
+		rules: [
+			{
+				test: /\.css$/,
+				use: [
+					{
+						loader: MiniCSSExtractPlugin.loader,
+					},
+					{
+						loader: require.resolve( 'css-loader' ),
+					},
+				],
+			},
+		],
+	},
+};