I was asked to complete a vague technical test, literally write any application in 2 days to "showcase my skills". They gave a list of 5 possible programming concepts to demonstrate and then stated that not all had to be covered and I could include extra concepts.
After wasting my time writing an application from scratch, I was contacted by the recruiter by phone that Datalex's engineers had looked at my application and it was missing some feature they wanted. This feature was not requested in their test. There was no other contact, not even one direct call with an engineer from Datalex about application.