Add tests for the lock-time-limit guard (#2381)

* Add tests for the lock-time-limit guard

* quick fix [ci-skip]

* quick fix [ci-skip]

---------

Co-authored-by: azahjessica49-commits <azahjessica49@gmail.com>
Co-authored-by: Baskar <baskarayelu@gmail.com>

Author: 3 people

quicklendx-contracts/src/lib.rs

@@ -193,6 +193,10 @@ mod test_evidence_kind_guard_matrix;
 #[cfg(all(test, feature = "legacy-tests"))]
 mod test_dispute_timeline_props;
 #[cfg(test)]
+mod test_due_date_guard;
+#[cfg(test)]
+mod test_lock_time_limit_guard;
+#[cfg(test)]
 // mod test_dispute_event_invariant;
 #[cfg(test)]
 mod test_dust_transfer;

quicklendx-contracts/src/test_lock_time_limit_guard.rs

@@ -0,0 +1,105 @@
+//! Lock-time-limit guard — "Within, at limit, past".
+//!
+//! Pins the time-window validation in
+//! `ProtocolLimitsContract::validate_invoice` across three zones:
+//!
+//! | Zone       | Lower bound                        | Upper bound                        |
+//! |------------|------------------------------------|------------------------------------|
+//! | **Within** | `due_date > current_time`          | `due_date < max_due_date`          |
+//! | **At limit** | `due_date == current_time`       | `due_date == max_due_date`         |
+//! | **Past**   | `due_date < current_time`          | `due_date > max_due_date`          |
+//!
+//! Every test is gated only by `#[cfg(test)]` so it runs on every CI matrix
+//! entry, not just when the `legacy-tests` feature is enabled.
+
+#![cfg(test)]
+
+use crate::errors::QuickLendXError;
+use crate::protocol_limits::ProtocolLimitsContract;
+use crate::QuickLendXContract;
+use soroban_sdk::{
+    testutils::{Address as _, Ledger},
+    Address, Env,
+};
+
+const SECONDS_PER_DAY: u64 = 86_400;
+
+fn setup_env() -> (Env, Address) {
+    let env = Env::default();
+    env.mock_all_auths();
+    env.ledger().set_timestamp(1_000_000);
+    let contract_id = env.register(QuickLendXContract, ());
+    (env, contract_id)
+}
+
+fn valid_amount() -> i128 {
+    100i128 // > DEFAULT_MIN_AMOUNT (10 in test builds)
+}
+
+// ---------------------------------------------------------------------------
+// Lower bound: due_date <= current_time → InvoiceDueDateInvalid
+// ---------------------------------------------------------------------------
+
+#[test]
+fn validate_invoice_rejects_due_date_past_lower_bound() {
+    let (env, contract_id) = setup_env();
+    let result = env.as_contract(&contract_id, || {
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), 999_999u64)
+    });
+    assert_eq!(result, Err(QuickLendXError::InvoiceDueDateInvalid));
+}
+
+#[test]
+fn validate_invoice_rejects_due_date_at_lower_bound() {
+    let (env, contract_id) = setup_env();
+    let result = env.as_contract(&contract_id, || {
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), 1_000_000u64)
+    });
+    assert_eq!(result, Err(QuickLendXError::InvoiceDueDateInvalid));
+}
+
+#[test]
+fn validate_invoice_accepts_due_date_within_lower_bound() {
+    let (env, contract_id) = setup_env();
+    let result = env.as_contract(&contract_id, || {
+        // due_date = current_time + 1, the first valid second
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), 1_000_001u64)
+    });
+    assert_eq!(result, Ok(()));
+}
+
+// ---------------------------------------------------------------------------
+// Upper bound: due_date > max_due_date → InvoiceDueDateInvalid
+// ---------------------------------------------------------------------------
+
+#[test]
+fn validate_invoice_accepts_due_date_within_upper_bound() {
+    let (env, contract_id) = setup_env();
+    let one_day_before_max = env.ledger().timestamp()
+        + 365 * SECONDS_PER_DAY
+        - 1;
+    let result = env.as_contract(&contract_id, || {
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), one_day_before_max)
+    });
+    assert_eq!(result, Ok(()));
+}
+
+#[test]
+fn validate_invoice_accepts_due_date_at_upper_bound() {
+    let (env, contract_id) = setup_env();
+    let max_due_date = env.ledger().timestamp() + 365 * SECONDS_PER_DAY;
+    let result = env.as_contract(&contract_id, || {
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), max_due_date)
+    });
+    assert_eq!(result, Ok(()));
+}
+
+#[test]
+fn validate_invoice_rejects_due_date_past_upper_bound() {
+    let (env, contract_id) = setup_env();
+    let past_max = env.ledger().timestamp() + 365 * SECONDS_PER_DAY + 1;
+    let result = env.as_contract(&contract_id, || {
+        ProtocolLimitsContract::validate_invoice(env.clone(), valid_amount(), past_max)
+    });
+    assert_eq!(result, Err(QuickLendXError::InvoiceDueDateInvalid));
+}