…#17803)

* add integration tests

* adjust import order to follow convention

* fixes to follow beam integration testing convention

* remove unused function and rename back to fakes_test.go

* import needed flags and read them properly

* unnest code in test

* add filters for specific runners

* add missing license

* rename member variable and use constant

* use better test files

* use gcpopts instead of pipeline options

* move testing logic to _test file

* filter direct runner as well since it doesnt provide the flags needed