Add config def. loading test

test/common/unit/config/Config.ts

@@ -0,0 +1,16 @@
+import {expect} from 'chai';
+import { ConfigClassBuilder } from 'typeconfig/node';
+import {ExtensionConfigWrapper} from '../../../../src/backend/model/extension/ExtensionConfigWrapper';
+
+
+describe('Config', () => {
+  it('should load default from env', () => {
+    process.env['default-Media-tempFolder'] = 'test/test'
+    const conf = ExtensionConfigWrapper.originalSync();
+    console.log(ConfigClassBuilder.attachPrivateInterface(conf.Media).__defaults);
+    expect(ConfigClassBuilder.attachPrivateInterface(conf.Media).__defaults.tempFolder).to.be.equal('test/test');
+    expect(process.env['default-Media-tempFolder']).to.be.equal('test/test');
+    const conf2 = ExtensionConfigWrapper.originalSync();
+    expect(ConfigClassBuilder.attachPrivateInterface(conf2.Media).__defaults.tempFolder).to.be.equal('test/test');
+  });
+});