Skip to main content

Unstable Vaadin UI tests

I have experienced a lot of issues with UI testing with Vaadin and Selenium. The test cases might seem to run OK initially but turn out very easily to be unstable, especially if the machine running tests is much faster/slower than the machine the tests have been written. The setups I have used contains some version of selenium, Robot framework, jBehave or CasperJS and PhantomJS, Chrome or Firefox. I haven't used the Vaadin Testbench. Here are my five cents to create stable Vaadin UI tests.

  • Don't use the in-built "is page loaded" methods, those rarely apply to single page JS apps.
  • Use the JS object "vaadin" and its properties isActive() and initialized to determine when it is OK to modify the UI.
  • Run in production mode, I have had a lot fewer issues like this.
  • Capture the browser logs, filter out there all info category messages and see if there are errors.
  • Use xpaths to find the correct elements. I have noticed that it helps if you wait first for some upper element and after that check that if the target element has appeared, so something like waitVisibity(//root-of-target) and then waitAndManipulate(//root-of-target/.../target) .
  • Sometimes the client<->server communication just breaks, especially with PhantomJS. I have no good solution for this, I just usually just refresh the page.
  • If you update the UI multiple times after the view has initially loaded and use WebSockets, doing manipulations during that time will most probably cause random issues. Wait until all data is pushed to the UI. The isActive() method may help but usually is too slow to keep up.
Labels:

Comments

Post a Comment

Popular posts from this blog

I'm not a passionate developer

A family friend of mine is an airlane pilot. A dream job for most, right? As a child, I certainly thought so. Now that I can have grown-up talks with him, I have discovered a more accurate description of his profession. He says that the truth about the job is that it is boring. To me, that is not that surprising. Airplanes are cool and all, but when you are in the middle of the Atlantic sitting next to the colleague you have been talking to past five years, how stimulating can that be? When he says the job is boring, it is not a bad kind of boring. It is a very specific boring. The "boring" you would want as a passenger. Uneventful.  Yet, he loves his job. According to him, an experienced pilot is most pleased when each and every tiny thing in the flight plan - goes according to plan. Passengers in the cabin of an expert pilot sit in the comfort of not even noticing who is flying. As someone employed in a field where being boring is not exactly in high demand, this sounds pro...
Post a Comment
Read more

PydanticAI + evals + LiteLLM pipeline

I gave a tech talk at a Python meetup titled "Overengineering an LLM pipeline". It's based on my experiences of building production-grade stuff with LLMs I'm not sure how overengineered it actually turned out. Experimental would be a better term as it is using PydanticAI graphs library, which is in its very early stages as of writing this, although arguably already better than some of the pipeline libraries. Anyway, here is a link to it. It is a CLI poker app where you play one hand against an LLM. The LLM (theoretically) gets better with a self-correcting mechanism based on the evaluation score from another LLM. It uses the annotated past games as an additional context to potentially improve its decision-making. https://github.com/juho-y/archipylago-poker
Post a Comment
Read more

Careful with externalTrafficPolicy

On a project I am working on is hosted in an EKS cluster with the NGINX ingress controller (the one maintained by Kubernetes). It is deployed using it's official official Helm chart, which I realized, after a lengthy debugging session, was a mistake. The initial setup I aimed to improve had several flaws. Firstly, we were using the AWS Classic Load Balancer in front of the nginx ingress in the cluster, which has been deprecated for some time (years?). Continuing to use it makes little sense to us. The second issue was that we were only running one(!) nginx pod, which is quite sketchy since the exposed web services had essentially no high availability.  I switched to the Network Load Balancer (NLB), which was straightforward - I just needed to change the ingress-nginx service annotation to specify the load balancer type as NLB: service.beta.kubernetes.io/aws-load-balancer-type: nlb However, increasing the replica count turned out to be tricky. When I bumped it up to two, I began to ...
Post a Comment
Read more