I don't think there should be a default value for the PCI address. This is too machine-dependent. Instead this test should 'skip' if the address is not set manually via the environment variable.

also: please match the existing style of the code for capitalisation. maybe not obvious, but in this code it's lower_case_with_underscores for all function/variable/constant names (but CamelCase for classes). I don't say it's the best :-))