More asserts

Added a couple more PhpUnit assertions, the goal is that all PhpUnit ones have a Verify counterpart. 
Sorry, there are 2 PRs with additional assertions, and probably I should have merged one of them.
Still I feel there are too much of redundant stuff. 
Verify is aimed to be as simple as possible. If you need some kind of file assertions you can use PHPUnit's assert* methods, they are ok. But most of assertions are not bound to file operations