fix(dataexport) - 12482 - Extract xml marshalling into library

- Add integration test on dataexport endpoint
- Add library with unit test for xml marshalling

test/api/unit/libs/xmlMarshaller.test.js

@@ -0,0 +1,44 @@
+import * as xmlMarshaller from '../../../../website/server/libs/xmlMarshaller';
+
+describe('xml marshaller marshalls user data', () => {
+  const minimumUser = {
+    pinnedItems: [],
+    unpinnedItems: [],
+    inbox: {},
+  };
+
+  function userDataWith (fields) {
+    return { ...minimumUser, ...fields };
+  }
+
+  it('maps the newMessages field to have id as a value in a list.', () => {
+    const userData = userDataWith({
+      newMessages: {
+        '283171a5-422c-4991-bc78-95b1b5b51629': {
+          name: 'The Language Hackers',
+          value: true,
+        },
+        '283171a6-422c-4991-bc78-95b1b5b51629': {
+          name: 'The Bug Hackers',
+          value: false,
+        },
+      },
+    });
+
+    const xml = xmlMarshaller.marshallUserData(userData);
+
+    expect(xml).to.equal(`<user>
+    <inbox/>
+    <newMessages>
+        <id>283171a5-422c-4991-bc78-95b1b5b51629</id>
+        <name>The Language Hackers</name>
+        <value>true</value>
+    </newMessages>
+    <newMessages>
+        <id>283171a6-422c-4991-bc78-95b1b5b51629</id>
+        <name>The Bug Hackers</name>
+        <value>false</value>
+    </newMessages>
+</user>`);
+  });
+});