We didn't reach the actual interview, there was a technical assessment before th e interview, which required the use of a certain framework, and the framework was not in a stable state (it had not even reached v1.x, it was 0.6.x), and when I installed the latest version of the framework it didn't include the package required for the assessment, so I went back to their github repo to get the previous stable versions which contain the package, but when I tried to use these versions, they always had errors in the basic skeleton app they generate, which shows that it is quite an unstable framework.
When I sent them about what happened, they replied once with an unhelpful suggestion, but I tried anyway, with no results, when I mailed them again, they didn't reply at all, which is quite unprofessional, since I have spent 2-3 days working on trying to setup the framework, and the required package, so they have wasted my time, without having the courtesy to even reply to me.
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Side note: This is not due to lack of my experience on my part, since I have been working with most of the tech stack that the framework utilizes for the past two years, so I know my way around most of it, the problem is with their framework of choice, and with their lack of respect for applicants' time.