feat: is_account_alive (#443)

closes #426

cairo/ethereum/cancun/state.cairo

@@ -529,3 +529,34 @@ func account_exists_and_is_empty{poseidon_ptr: PoseidonBuiltin*, state: State}(
     tempvar res = bool(1);
     return res;
 }
+
+func is_account_alive{poseidon_ptr: PoseidonBuiltin*, state: State}(address: Address) -> bool {
+    let account = get_account_optional(address);
+    if (cast(account.value, felt) == 0) {
+        tempvar res = bool(0);
+        return res;
+    }
+
+    if (account.value.nonce.value != 0) {
+        tempvar res = bool(1);
+        return res;
+    }
+
+    if (account.value.code.value.len != 0) {
+        tempvar res = bool(1);
+        return res;
+    }
+
+    if (account.value.balance.value.low != 0) {
+        tempvar res = bool(1);
+        return res;
+    }
+
+    if (account.value.balance.value.high != 0) {
+        tempvar res = bool(1);
+        return res;
+    }
+
+    tempvar res = bool(0);
+    return res;
+}

cairo/tests/ethereum/cancun/test_state.py

@@ -16,6 +16,7 @@
     get_account_optional,
     get_storage,
     get_transient_storage,
+    is_account_alive,
     is_account_empty,
     set_account,
     set_storage,
@@ -110,6 +111,13 @@ def test_account_exists_and_is_empty(self, cairo_run, data):
         assert result_cairo == account_exists_and_is_empty(state, address)
         assert state_cairo == state
 
+    @given(data=state_and_address_and_optional_key())
+    def test_is_account_alive(self, cairo_run, data):
+        state, address = data
+        state_cairo, result_cairo = cairo_run("is_account_alive", state, address)
+        assert result_cairo == is_account_alive(state, address)
+        assert state_cairo == state
+
 
 class TestStateStorage:
     @given(data=state_and_address_and_optional_key(key_strategy=bytes32))