Disable test_r_recommends test
autodep8 fails with the error,
[ 167s] [1;31mASSERT:[0mNo r-cran-brew in Depends
[ 167s] [1;31mshunit2:ERROR[0m test_r_recommends() returned non-zero return code.The autodep8 generator for pkg-r-autopkgtest uses APT lists to determine which R packages from DESCRIPTION exist in Debian. autodep8 is run outside the test runner, not inside it, so this makes the behaviour dependant on the packages available to the test runner host.
So disable the failing test.