Add basic load test

packages/mindplot/test/unit/export/PlainTextExportTestSuite.test.ts

@@ -0,0 +1,23 @@
+import PlainTextExporter from '../../../src/components/export/PlainTextExporter';
+import Mindmap from '../../../src/components/model/Mindmap';
+import XMLSerializerTango from '../../../src/components/persistence/XMLSerializerTango';
+import fs from  'fs';
+import path from 'path';
+
+test('mindplot generation of simple maps', () => {
+
+  // Load DOM ...
+  const mapStream =fs.readFileSync(path.resolve(__dirname, '../samples/welcome.xml'),{encoding: 'utf-8'});
+  const parser = new DOMParser();
+  const document = parser.parseFromString(mapStream.toString(), 'text/xml')
+  
+  // Convert to mindmap ...
+  const serializer = new XMLSerializerTango();
+  const mindmap:Mindmap = serializer.loadFromDom(document,'welcome');
+
+  // Inspect ...
+  console.log(mindmap);
+ 
+  const exporter = new PlainTextExporter(mindmap);
+  console.log(exporter.export());
+});