For these types of tests, the test name is previously recorded in a
variable, not passed to the test function, so pass this variable to
test_skip.
 
        output="$1"
        expected="$2"
-       if ! test_skip "$@"
+       if ! test_skip "$test_subtest_name"
        then
                if [ "$output" = "$expected" ]; then
                        test_ok_ "$test_subtest_name"
 
        output="$1"
        expected="$2"
-       if ! test_skip "$@"
+       if ! test_skip "$test_subtest_name"
        then
                if diff -q "$expected" "$output" >/dev/null ; then
                        test_ok_ "$test_subtest_name"