Updated coverage

src/app.js

@@ -160,7 +160,7 @@ module.exports = (config) => {
           });
         lastRSS = feed.xml();
       }
-      res.type(req.headers['user-agent'].match(/Mozilla/) ? 'xml' : 'rss').send(lastRSS);
+      res.type(req.headers['user-agent'].match(/Mozilla/) ? 'text/xml' : 'rss').send(lastRSS);
     } else {
       showError(req.path, 404, res);
     }

test/app.test.js

@@ -181,6 +181,13 @@ describe('Test RSS feed', () => {
       done();
     });
   });
+  test('200 Mozilla fix', (done) => {
+    request(app).get('/rsstest').set('user-agent', 'Mozilla Firefox 64.0').then((response) => {
+      expect(response.statusCode).toBe(200);
+      expect(response.type).toBe('text/xml');
+      done();
+    });
+  });
   test('200 rss cache', (done) => {
     request(app).get('/rsstest').then(() => {
       request(app).get('/rsstest').then((response) => {