Move service tests alongside code (#1563)

Per discussion in #1543

services/amo/amo.tester.js

@@ -0,0 +1,57 @@
+'use strict';
+
+const Joi = require('joi');
+const ServiceTester = require('../service-tester');
+const {
+  isMetric,
+  isStarRating,
+  isVPlusDottedVersionAtLeastOne,
+} = require('../test-validators');
+
+const t = new ServiceTester({ id: 'amo', title: 'Mozilla Addons' });
+module.exports = t;
+
+t.create('Downloads')
+  .get('/d/IndieGala-Helper.json')
+  .expectJSONTypes(Joi.object().keys({ name: 'downloads', value: isMetric }));
+
+t.create('Version')
+  .get('/v/IndieGala-Helper.json')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'mozilla add-on',
+    value: isVPlusDottedVersionAtLeastOne
+  }));
+
+t.create('Version - Custom label')
+  .get('/v/IndieGala-Helper.json?label=IndieGala Helper')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'IndieGala Helper',
+    value: isVPlusDottedVersionAtLeastOne
+  }));
+
+t.create('Users')
+  .get('/users/IndieGala-Helper.json')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'users',
+    value: Joi.string().regex(/^\d+$/)
+  }));
+
+t.create('Rating')
+  .get('/rating/IndieGala-Helper.json')
+  .expectJSONTypes(Joi.object().keys({
+    name: 'rating',
+    value: Joi.string().regex(/^\d\/\d$/)
+  }));
+
+t.create('Stars')
+  .get('/stars/IndieGala-Helper.json')
+  .expectJSONTypes(Joi.object().keys({ name: 'stars', value: isStarRating }));
+
+t.create('Invalid addon')
+  .get('/d/invalid-name-of-addon.json')
+  .expectJSON({ name: 'mozilla add-on', value: 'invalid' });
+
+t.create('No connection')
+  .get('/v/IndieGala-Helper.json')
+  .networkOff()
+  .expectJSON({ name: 'mozilla add-on', value: 'inaccessible' });