Move service tests alongside code (#1563)

Per discussion in #1543

services/node/node.tester.js

@@ -0,0 +1,45 @@
+'use strict';
+
+const { expect } = require('chai');
+const Joi = require('joi');
+const ServiceTester = require('../service-tester');
+const { Range } = require('semver');
+
+const t = new ServiceTester({ id: 'node', title: 'Node' });
+module.exports = t;
+
+function expectSemverRange(value) {
+  expect(() => {
+    // eslint-disable-next-line no-new
+    new Range(value);
+  }).not.to.throw(null, null, 'Expected value to be a semver range');
+}
+
+t.create('gets the node version of passport')
+  .get('/v/passport.json')
+  .expectJSONTypes(Joi.object({ name: 'node' }).unknown())
+  .afterJSON(json => { expectSemverRange(json.value); });
+
+t.create('gets the node version of @stdlib/stdlib')
+  .get('/v/@stdlib/stdlib.json')
+  .expectJSONTypes(Joi.object({ name: 'node' }).unknown())
+  .afterJSON(json => { expectSemverRange(json.value); });
+
+t.create("gets the tagged release's node version version of ionic")
+  .get('/v/ionic/next.json')
+  .expectJSONTypes(Joi.object({ name: 'node@next' }).unknown())
+  .afterJSON(json => { expectSemverRange(json.value); });
+
+t.create('gets the node version of passport from a custom registry')
+  .get('/v/passport.json?registry_uri=https://registry.npmjs.com')
+  .expectJSONTypes(Joi.object({ name: 'node' }).unknown())
+  .afterJSON(json => { expectSemverRange(json.value); });
+
+t.create("gets the tagged release's node version of @cycle/core")
+  .get('/v/@cycle/core/canary.json')
+  .expectJSONTypes(Joi.object({ name: 'node@canary' }).unknown())
+  .afterJSON(json => { expectSemverRange(json.value); });
+
+t.create('invalid package name')
+  .get('/v/frodo-is-not-a-package.json')
+  .expectJSON({ name: 'node', value: 'package not found' });