Configuration for the test program. If either field is not zero then the
test program will try to match these fields against the corresponding
fields in UDP packets. In that case, if a packet doesn’t match or it’s not
a UDP packet the program returns 0 without updating the TestResult. If
both fields are zero or the packet matches then TestResult is updated
and the program returns 1.
Struct used to store results of the last invocation of the test program
to test. The program copies the corresponding fields from the packet to
this struct. Test can read it using TestProgram::read_test_result().