[#11]add test to include arbitrary library

Add test to make it possible to include arbitrary library into the
function

lib/domain/sandbox/SandboxRequire.js

@@ -30,7 +30,7 @@ class SandboxRequire {
   generateRequire() {
     return (requireName) => {
       let requestedModule;
-      if (this.module[requireName] !== undefined) {
+      if (this.module && this.module[requireName] !== undefined) {
         requestedModule = this.module[requireName]();
       } else if (this.globalModules.indexOf(requireName) !== -1) {
         requestedModule = requireFunction(requireName);

test/integration/domain/http/routers/FunctionsRouter.text.js

@@ -144,5 +144,30 @@ describe('FunctionRouter integration', () => {
           }, done);
       });
     });
+
+    describe('require arbitrary library inside function', () => {
+      before((done) => {
+        const code = `
+          const _ = require('lodash');
+          const people = [{name: 'John'}, {name: 'Doe'}];
+          function main(req, res) {
+            const names = _.map(people, 'name');
+            res.send({ names });
+          }
+        `;
+
+        request(routes)
+          .put('/functions/function-router-run/test4').send({ code })
+          .expect(200).expect('content-type', /json/, done);
+      });
+
+      it('should uses the arbitrary library properly', (done) => {
+        request(routes)
+          .put('/functions/function-router-run/test4/run')
+          .expect(200)
+          .expect('content-type', /json/)
+          .expect({ names: ['John', 'Doe']}, done);
+      });
+    });
   });
 });