Expose message Ids to the user

backend/src/Model/spec/Tree.spec.ts

@@ -1,18 +1,16 @@
 import 'mocha'
-
-import { Tree, TreeNodeFactory } from '../'
-
 import { expect } from 'chai'
+import { Tree } from '../'
+import { makeTreeNode } from './makeTreeNode'
 
 describe('Tree', () => {
   it('node can be merged into a tree', () => {
     const tree = new Tree()
-
-    const topics = 'foo/bar'.split('/')
-    const leaf = TreeNodeFactory.fromEdgesAndValue(topics, undefined)
+    const leaf = makeTreeNode('foo/bar')
 
     tree.updateWithNode(leaf.firstNode())
     const expectedNode = tree.findNode('foo/bar')
+
     expect(expectedNode).to.eq(leaf)
   })
 })