make sure that constants are verified

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
allow should usage for now in spec/

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>
include rspec/its in bats

Signed-off-by: dmitriy kalinin <dmitriy@pivotallabs.com>