测试同构javascript应用程序

Question

I have a Javascript application that consists of client-side code and server-side (Node/Express) code. Is there a testing solution that covers both client and server, or do you have to run seperate test frameworks for each?

Reason I ask is because I am trying to share code between client and server, eg a helper function that generates a unique id. Is this a good idea, or is it better to separate the concerns?

Answer 1

This is a complicated question with multiple answers. tl;dr You can do a lot of testing server side, but usually at some point you end up wanting client side tests.

In many respects, even though javascript applications can be isomorphic, the actual execution environment of client side vs. server side is very different when it comes to globals and language features. To be a completionist on testing-- one would need to have both client side and server side testing.

From a more pragmatic standpoint-- depending on the implementation and modularity of the javascript application one can choose to minimize or eliminate entirely the client side testing with the following methods: - Use jsdom to replace the DOM api in node - For isomorphic React applications use jest + react-addons-test-utils and/or enzyme as test harnesses into component instances - Stub out browser globals as needed and test modules in isolation

At some point though, you almost always want to spin up a browser for "real world" testing. This could come in the form of holistic solutions like karma or rolling your own with mocha + browserify / webpack for units tests or nightwatch for integration / acceptance tests.

Besides the browser globals, the other important distinction between server side and client side tests is that server side tests never have any dynamic behavior. That lives entirely in the client. To the amount your application depends on browser features, rather than isomorphic library features (eg pure React) then you will find a greater and greater need for client side testing.