Improve `workbench` command error message

This will check the `package` argument of the `workbench` command and output a more friendly message if the package name is not correct.
I also added some tests here.

Solve #4606 
If you put the `m::close` inside the constructor, errors with mocking object will not be collected at the end of `ViewTest` test. I determined this incorrect behavior when running `PHPUnit` in the 4244f89c67f13d746d68a1578ad0e03d0b0be8bf commit. Some errors which was not decteded from `ViewTest` was reported.