div mod tests (#238)

Adds basic tests for div_mod

## Pull Request type

<!-- Please try to limit your pull request to one type; submit multiple
pull requests if needed. -->

Please check the type of change your PR introduces:

- [ ] Bugfix
- [ ] Feature
- [ ] Code style update (formatting, renaming)
- [x] Refactoring (no functional changes, no API changes)
- [ ] Build-related changes
- [ ] Documentation content changes
- [ ] Other (please describe):

## What is the current behavior?

No div_mod test.

## What is the new behavior?

Basic div_mod test added.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this does introduce a breaking change, please describe the
impact and migration path for existing applications below. -->

## Other information

For 30 / 10 test,


![image](https://github.com/keep-starknet-strange/alexandria/assets/11048263/efe3e0a5-5a3e-45ca-92fb-7b27cdb6ef7f)

src/math/src/tests/mod_arithmetics_test.cairo

@@ -112,6 +112,16 @@ fn mult_mod_2_test() {
     assert(mult_mod(pow_256_minus_1, 1, 2) == 1, 'Incorrect result');
 }
 
+#[test]
+#[available_gas(500000000)]
+fn div_mod_test() {
+    let div_10_30_mod_p =
+        38597363079105398474523661669562635951089994888546854679819194669304376546633;
+    assert(div_mod(p, 1, p) == 0, 'Incorrect result');
+    assert(div_mod(30, 10, p) == 3, 'Incorrect result');
+    assert(div_mod(10, 30, p) == div_10_30_mod_p, 'Incorrect result');
+}
+
 #[test]
 #[available_gas(500000000)]
 fn pow_mod_test() {