Add [twitter] tests

server.js

@@ -6403,18 +6403,20 @@ cache(function(data, match, sendBadge, request) {
   badgeData.text[1] = '';
   request(options, function(err, res, buffer) {
     if (err != null) {
+      badgeData.text[1] = 'inaccessible';
       sendBadge(format, badgeData);
       return;
     }
     try {
       // The data is formatted as an array.
       var data = JSON.parse(buffer)[0];
-      // data.followers_count could be zero… don't just check if falsey.
-      if (data !== undefined && data.followers_count != null){
+      if (data === undefined){
+        badgeData.text[1] = 'invalid user';
+      } else if (data.followers_count != null){// data.followers_count could be zero… don't just check if falsey.
         badgeData.text[1] = metric(data.followers_count);
       }
     } catch(e) {
-      log.error(e);
+      badgeData.text[1] = 'invalid';
     }
     sendBadge(format, badgeData);
   });

service-tests/twitter.js

@@ -0,0 +1,41 @@
+'use strict';
+
+const Joi = require('joi');
+const ServiceTester = require('./runner/service-tester');
+
+const {
+  isMetric
+} = require('./helpers/validators');
+
+const t = new ServiceTester({ id: 'twitter', title: 'Twitter' });
+module.exports = t;
+
+t.create('Followers')
+  .get('/follow/shields_io.json')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'Follow @shields_io',
+    value: isMetric
+  }));
+
+t.create('Followers - Custom Label')
+  .get('/follow/shields_io.json?label=Follow')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'Follow',
+    value: isMetric
+  }));
+
+t.create('Invalid Username Specified')
+  .get('/follow/invalidusernamethatshouldnotexist.json?label=Follow')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'Follow',
+    value: 'invalid user'
+  }));
+
+t.create('No connection')
+  .get('/follow/shields_io.json?label=Follow')
+  .networkOff()
+  .expectJSON({ name: 'Follow', value: 'inaccessible' });
+
+t.create('URL')
+  .get('/url/https/shields.io.json')
+  .expectJSON({ name: 'tweet', value: '' });