cat <<'EOF' > expected
A is defined
A is undefined
EOF
test_diff <<'EOF'
int printf();
int main() {
#define A 1
#ifdef A
printf("A is defined\n");
#else
printf("A is undefined\n");
#endif
#undef A
#ifdef A
printf("A is defined\n");
#else
printf("A is undefined\n");
#endif
}
EOF