testfileset('remove all', $BASICBODY, [qr/./ => undef], 4, '');
testfileset('add unconditionally', "$/0$/", [undef() => '0'], 1, "$/0$/0$/");
testfileset('add string', "foo$/", ['bar'], 1, "foo$/bar$/");
testfileset('keep string', "foo$/bar$/", ['foo'], 0, "foo$/bar$/");
testfileset('keep first', "foo$/FOO$/foo$/", ['foo'], 1, "foo$/FOO$/");
testfileset('remove all', $BASICBODY, [qr/./ => undef], 4, '');
testfileset('add unconditionally', "$/0$/", [undef() => '0'], 1, "$/0$/0$/");
testfileset('add string', "foo$/", ['bar'], 1, "foo$/bar$/");
testfileset('keep string', "foo$/bar$/", ['foo'], 0, "foo$/bar$/");
testfileset('keep first', "foo$/FOO$/foo$/", ['foo'], 1, "foo$/FOO$/");