Hi guys,
I am learning CSS and HTML and toughly learn the code flexible for accessibility 
. I recognize the increasing focus on accessibility in software development, I wonder how can testing help ensure that software is accessible to people with disabilities? Is there anyone has the experience with this and suggest some common accessibility testing tools and techniques? 
I did that in the past.
It is a separate domain of manual testing mostly, has to be done carefully.
Some stuff can be automated … in the sense that, are some tools here and there which can help the tester to focus on certain ‘flags’.
But it requires a skilled QA engineer and final validation should be done by a human person only.
Mostly, the QA engineer should use tools and act like he is actually affected by various disabilities.
Trust me, it is not that easy 
You can start to read about such here:
https://www.w3.org/wiki/Accessibility_testing
Yeah, I agree it is not easy :)). I have a question on the very first step - Coding: Is it true that a code with more CSS flexible with more accessibility cases will be easier to test?
I see in the reference, there are several personas with accessibilities:
Should we try to cover all of them?
The reference advices the standard of WCAG 2.0, while my learning from my resources is ARIA. Which one is more commonly used now?
The compliance level is usually defined into the contract between the development company and the client, so it may vary.
Some clients may opt for more relaxed policy, e. g an older WCAG.
But a skilled tester should be familiar with all types of them and be prepared for the most demanding.
Not everything can be automated, e. g for visual impaired manual testing / confirmation is mandatory even some preliminary assesment can be made by automation.
Also the tester should confirm with the client the compliance level, through BA, PO PM etc to not waste his time and focus only on what is needed.
Aside of that, a skilled developper will also implement the UI with most of the requirements fulfilled, generally the rules have common sense… but if the compliance level is not clearly requested, they may became lazy.
In addition of the above, the UI/UX designer plays a very important role. If the collor palette and the navigation ‘workflow’ are properly designed, all may be good, the developper will just implement them as requested without wasting time on digging and thinking ‘what is the best way to do this’
So, having in mind that, in a normal development cycle, you may have all the key persons in place, but the chain it is still ‘long’ and have various ‘point of failures’.
If no such key-persons are provided for the project, it’s even worse.
So, testing is a must!
