docs,test(savings): document and test create_goal past target_date be…

savings_goals/src/lib.rs

@@ -522,6 +522,14 @@ impl SavingsGoalContract {
     // Core goal operations
     // -----------------------------------------------------------------------
 
+    /// Creates a new savings goal.
+    ///
+    /// - `owner` must authorize the call.
+    /// - `target_amount` must be positive.
+    /// - `target_date` is stored as provided and may be in the past. This
+    ///   supports backfill or migration use cases where historical goals are
+    ///   recorded after the fact. Callers that need strictly future-dated
+    ///   goals should validate this before invoking the contract.
     pub fn create_goal(
         env: Env,
         owner: Address,

savings_goals/src/test.rs

@@ -25,6 +25,31 @@ fn test_create_goal_unique_ids_succeeds() {
     assert_ne!(id1, id2);
 }
 
+/// Documented behavior: past target dates are allowed (e.g. for backfill or
+/// data migration). This test locks in that create_goal accepts a target_date
+/// earlier than the current ledger timestamp and persists it as provided.
+#[test]
+fn test_create_goal_allows_past_target_date() {
+    let env = Env::default();
+    let contract_id = env.register_contract(None, SavingsGoalContract);
+    let client = SavingsGoalContractClient::new(&env, &contract_id);
+    let user = Address::generate(&env);
+
+    client.init();
+    env.mock_all_auths();
+
+    // Move ledger time forward so our target_date is clearly in the past.
+    set_time(&env, 2_000_000_000);
+    let past_target_date = 1_000_000_000u64;
+
+    let name = String::from_str(&env, "Backfill Goal");
+    let id = client.create_goal(&user, &name, &1000, &past_target_date);
+
+    assert_eq!(id, 1);
+    let goal = client.get_goal(&id).unwrap();
+    assert_eq!(goal.target_date, past_target_date);
+}
+
 // ============================================================================
 // init() idempotency and NEXT_ID behavior
 //

savings_goals/tests/stress_test_large_amounts.rs

@@ -141,6 +141,43 @@ fn test_add_to_goal_overflow_panics() {
     env.mock_all_auths();
     client.add_to_goal(&owner, &goal_id, &overflow_amount);
 }
+#[test]
+fn test_withdraw_from_goal_with_large_amount() {
+    let env = Env::default();
+    let contract_id = env.register_contract(None, SavingsGoalContract);
+    let client = SavingsGoalContractClient::new(&env, &contract_id);
+    let owner = <soroban_sdk::Address as AddressTrait>::generate(&env);
+
+    env.mock_all_auths();
+
+    let large_target = i128::MAX / 2;
+    let large_amount = i128::MAX / 4;
+
+    let goal_id = client.create_goal(
+        &owner,
+        &String::from_str(&env, "Large Goal"),
+        &large_target,
+        &2000000,
+    );
+
+    // Add funds
+    env.mock_all_auths();
+    client.add_to_goal(&owner, &goal_id, &large_amount);
+
+    // Unlock to allow withdrawal
+    env.mock_all_auths();
+    client.unlock_goal(&owner, &goal_id);
+
+    // Withdraw half
+    env.mock_all_auths();
+    let to_withdraw = large_amount / 2;
+    let remaining = client.withdraw_from_goal(&owner, &goal_id, &to_withdraw);
+
+    // For odd large_amount values, large_amount - (large_amount / 2) equals
+    // ceil(large_amount / 2), not exactly large_amount / 2. Assert on the
+    // invariant instead of assuming evenness.
+    assert_eq!(remaining + to_withdraw, large_amount);
+}
 // #[test]
 // fn test_withdraw_from_goal_with_large_amount() {
 //     let env = Env::default();