feat: Add clean method for list (#182)

## Pull Request type

Please check the type of change your PR introduces:

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

## What is the current behavior?

Issue Number:
[#177](#177)

## What is the new behavior?

- Added a clean component to List 
- Added unit test related to this component

## Does this introduce a breaking change?

- [ ] Yes
- [X] No

## Other information

Author: azurwastaken

src/storage/src/list.cairo

@@ -25,6 +25,7 @@ trait ListTrait<T> {
     fn append(ref self: List<T>, value: T) -> u32;
     fn get(self: @List<T>, index: u32) -> Option<T>;
     fn set(ref self: List<T>, index: u32, value: T);
+    fn clean(ref self: List<T>);
     fn pop_front(ref self: List<T>) -> Option<T>;
     fn array(self: @List<T>) -> Array<T>;
 }
@@ -71,6 +72,11 @@ impl ListImpl<T, impl TCopy: Copy<T>, impl TDrop: Drop<T>, impl TStore: Store<T>
         Store::write_at_offset(self.address_domain, base, offset, value).unwrap_syscall();
     }
 
+    fn clean(ref self: List<T>) {
+        self.len = 0;
+        Store::write(self.address_domain, self.base, self.len);
+    }
+
     fn pop_front(ref self: List<T>) -> Option<T> {
         if self.len == 0 {
             return Option::None;

src/storage/src/tests/list_test.cairo

@@ -13,6 +13,7 @@ trait IAListHolder<TContractState> {
     fn do_set(
         ref self: TContractState, index: u32, addrs_value: ContractAddress, numbers_value: u256
     );
+    fn do_clean(ref self: TContractState);
     fn do_pop_front(ref self: TContractState) -> (Option<ContractAddress>, Option<u256>);
     fn do_array(self: @TContractState) -> (Array<ContractAddress>, Array<u256>);
 }
@@ -67,6 +68,13 @@ mod AListHolder {
             n.set(index, numbers_value);
         }
 
+        fn do_clean(ref self: ContractState) {
+            let mut a = self.addrs.read();
+            let mut n = self.numbers.read();
+            a.clean();
+            n.clean();
+        }
+
         fn do_pop_front(ref self: ContractState) -> (Option<ContractAddress>, Option<u256>) {
             let mut a = self.addrs.read();
             let mut n = self.numbers.read();
@@ -359,4 +367,52 @@ mod tests {
         let (array_addr, array_number) = contract.do_array();
         assert((array_addr.len(), array_number.len()) == (0, 0), 'lens must be null');
     }
+
+    #[test]
+    #[available_gas(100000000)]
+    fn test_array_clean() {
+        let contract = deploy_mock();
+        let mock_addr = mock_addr();
+
+        contract.do_append(mock_addr, 100); // idx 0
+        contract.do_append(mock_addr, 200); // idx 1
+        contract.do_append(mock_addr, 300); // idx 2
+        contract.do_clean();
+        assert(contract.do_get_len() == (0, 0), 'is empty');
+    }
+
+    #[test]
+    #[available_gas(100000000)]
+    fn test_array_clean_with_empty_array() {
+        let contract = deploy_mock();
+        let mock_addr = mock_addr();
+
+        assert(contract.do_get_len() == (0, 0), 'is empty');
+
+        contract.do_clean();
+
+        assert(contract.do_get_len() == (0, 0), 'is still empty');
+    }
+
+    #[test]
+    #[available_gas(100000000)]
+    fn test_array_get_value_after_clean() {
+        let contract = deploy_mock();
+        let mock_addr = mock_addr();
+
+        contract.do_append(mock_addr, 100); // idx 0
+        let (addr, number) = contract.do_get(0);
+        assert(addr.is_some(), 'addr is some');
+        assert(addr.unwrap() == mock_addr, 'should be mock_addr');
+        assert(number.is_some(), 'number is some');
+        assert(number.unwrap() == 100, 'should be 100');
+
+        contract.do_clean();
+
+        assert(contract.do_get_len() == (0, 0), 'len');
+
+        let (addr, number) = contract.do_get(0);
+        assert(addr.is_none(), 'addr is none');
+        assert(number.is_none(), 'number is none');
+    }
 }