Overall tests are good. They prepare for what you could expect on the exam. But there are so many issues with the questions, especially with missing type parameters for generic types. This is extremely important for lambdas and if they will compile or not. Yet so many questions do not have type parameters. Sometime this is on purpose, in most cases this is by mistake. Also font is terrible for reading the code.
I agree - there are so many incorrect answers that I simply didn't trust the others, even if they were correct. I provided feedback on the faulty questions, wrote to support, and wrote a review and got no meaningful response. They have not published my review. I WILL NOT BUY ANY FURTHER PRODUCTS FROM WHIZLABS