测试Thymeleaf表单/ Spring MVC Controller交互的最佳方法

Question

I am working on a Spring Boot app using Thymeleaf & Spring MVC, and I came across a bug in the code where someone had bound the Spring MVC model to 2 different HTML form fields:

<input th:field="*{userModel.name}" type="text" />
<input id="name" th:field="*{userModel.name}" type="hidden" />

This was causing the name field in the model of the controller to get set to a string of comma-separated values. "Steve,Steve" for example. I fixed the problem, but I'm wondering the simplest way to write a regression test for this. There is a Spring MVC testing framework, which I could use as on this blog post , but what I really want to test is the interaction between the rendered template and the controller, not just the controller.

I could use a selenium test, but I recently read this Martin Fowler bliki/article (blikticle?) in which he says:

In particular a common problem is that teams conflate the concepts of end-to-end tests, UI tests, and customer facing tests. These are all orthogonal characteristics.

I think this is a great point. What I would like to write is a UI component (integration?) test, I think. Something smaller than loading up the whole page. Something only testing the form generation and submission.

Another idea I had was that this sort of bug might be best caught through a static-analysis tool, but that's a bit beyond my scope.

In this project, I've realized that the interactions between Spring MVC and the HTML forms are a common place for errors, so it would be nice to have a way to test just these interactions.

EDIT:

Upon further consideration, I think these are the steps I want in my test:

1. Select <form> tag out of a template's thymeleaf template and render it, passing in appropriate data on the model
2. Possibly programmatically edit the rendered form values (from Java) to simulate JavaScript interactions.
3. Generate a browser's http POST request based on rendered form.
4. Use whatever Spring uses to convert POST request to the controller's model parameter
5. Either call the controller and verify the results, or just assert that the model was created correctly

I think I may able to do #1 with Thymeleaf's fragment selectors or by refactoring my form out into a separate template. #2 I can do easily with JSoup. It's #3 & #4 that I'm not sure how to do. #3 I might be able to write myself maybe, depending on how the HttpServletRequest mocks work. #4 seems like it's gotta be available in Spring somewhere but I'm new to Spring.

UPDATE:

Looking at the WebDataBinder as a possible solution for #4.

Answer 1

I think you should test the functionality and to get good path-coverage of the controller calling the controller directly, mocking the underlying services. Then you can test if the model is correctly filled.

You can test a complex template with Thymeleaf-test infrastructure.

However, at the end of the day, everything must work together. This test should be done with selenium, to check the the variable-names match (So your regression). Normally you should only need a few tests for each page. If you have a lot of JS you should test complex JS functionality with buster.js. The htmlunitdriver of selenium is really fast, so I assume that the performance shouldn't be a big issue. But don't test all controller- or service-paths with selenium.

Answer 2

A few years later, it looks like you can do now essentially what I wanted using HtmlUnit/SpringMVC Test integration. It will shortcut any calls you make to your controller and use MockMVC instead, without a Servlet Container.

So, you get the advantage of a html-smart client library to wrap the front end like a browser without the overhead of the servlet container and with the ability to mock out whatever you want to under the controller.

https://docs.spring.io/spring/docs/current/spring-framework-reference/testing.html#spring-mvc-test-server-htmlunit