Add tests for resolving using webpack resolve.root

package.json

@@ -42,7 +42,7 @@
     "commander": "^2.9.0",
     "commondir": "^1.0.1",
     "debug": "^2.2.0",
-    "dependency-tree": "^5.7.1",
+    "dependency-tree": "^5.7.5",
     "graphviz": "^0.0.8",
     "mz": "^2.4.0",
     "rc": "^1.1.6",

test/es6.js

@@ -51,4 +51,17 @@ describe('ES6', () => {
 			done();
 		}).catch(done);
 	});
+
+	it('supports resolve root paths in webpack config', (done) => {
+		madge(dir + '/webpack/src/sub/index.js', {
+			webpackConfig: dir + '/webpack/webpack.config.js'
+		}).then((res) => {
+			res.obj().should.eql({
+				'index': ['rel'],
+				'abs': [],
+				'rel': ['abs']
+			});
+			done();
+		}).catch(done);
+	});
 });

test/es6/webpack/src/sub/index.js

@@ -0,0 +1 @@
+import rel from './rel.js';

test/es6/webpack/src/sub/rel.js

@@ -0,0 +1 @@
+import abs from 'sub/abs.js';

test/es6/webpack/webpack.config.js

@@ -0,0 +1,9 @@
+'use strict';
+
+const path = require('path');
+
+module.exports = {
+	resolve: {
+		root: path.resolve(__dirname, './src')
+	}
+};