void test_sub_underflows_to_bignum() {
Fixnum* min = Fixnum::from(FIXNUM_MIN);
Integer* min_minus1 = min->sub(state, Fixnum::from(1));
TS_ASSERT(kind_of<Bignum>(min_minus1));
TS_ASSERT_EQUALS(FIXNUM_MIN-1, min_minus1->to_native());
}
void test_sub() {
Fixnum* one = Fixnum::from(1);
Fixnum* zero = as<Fixnum>(one->sub(state, one));
TS_ASSERT_EQUALS(0, zero->to_native());
TS_ASSERT_EQUALS(Fixnum::from(0), zero);
}
void test_sub_overflows_to_bignum() {
Fixnum* max = Fixnum::from(FIXNUM_MAX);
Integer* max_plus1 = max->sub(state, Fixnum::from(-1));
TS_ASSERT(kind_of<Bignum>(max_plus1));
TS_ASSERT_EQUALS(FIXNUM_MAX+1, max_plus1->to_native());
}
void test_sub_a_bignum() {
Fixnum* one = as<Fixnum>(Fixnum::from(13));
Bignum* obj = Bignum::from(state, (native_int)FIXNUM_MAX + 28);
Integer* res = one->sub(state, obj);
TS_ASSERT(kind_of<Bignum>(res));
TS_ASSERT_EQUALS(res->to_native(), 13 - (FIXNUM_MAX + 28));
}
void test_sub_a_float() {
Fixnum* one = Fixnum::from(13);
Float* res = one->sub(state, Float::create(state, 1.4));
check_float(res, Float::create(state, 11.6));
}