From what I have heard it used to be one of the most difficult tests within aviation. I am very familiar with the company myself, and got alot of connections within that gives me all sorts of info regarding windows of recruitment and insight of the tests.
What they all agree on is that the tests are harder than it should be, and many people fail this stage.
Working conditions are good, they used to have 7/7-roster, all extras that you expect from a well run company, and the pay is good. Mind that Norwegian way of living is an expensive one!