Fix rounding on cancel (#310)

* Fix on cancel rounding

* add back rule

* fmt

programs/manifest/rules.json

@@ -60,6 +60,12 @@
       "prover_options": [],
       "cargo_features": []
     },
+    {
+      "name": "rule_cancel_order_by_index_bid",
+      "expected_result": "Verified",
+      "prover_options": [],
+      "cargo_features": []
+    },
     {
       "name": "rule_cancel_order_by_index_ask",
       "expected_result": "Verified",

programs/manifest/src/state/market.rs

@@ -1362,10 +1362,13 @@ impl<
 
         let resting_order: &RestingOrder = get_helper_order(dynamic, order_index).get_value();
         let is_bid: bool = resting_order.get_is_bid();
+
+        // Important to round up because there was an extra atom taken for full
+        // taker rounding when the order was placed.
         let amount_atoms: u64 = if is_bid {
             (resting_order
                 .get_price()
-                .checked_quote_for_base(resting_order.get_num_base_atoms(), false)
+                .checked_quote_for_base(resting_order.get_num_base_atoms(), true)
                 .unwrap())
             .into()
         } else {

programs/manifest/tests/cases/cancel_order.rs

@@ -42,6 +42,28 @@ async fn cancel_order_bid_test() -> anyhow::Result<()> {
     Ok(())
 }
 
+// This test failed when the rounding on cancel was incorrect. Now it passes. It
+// shows that all funds are retrievable.
+#[tokio::test]
+async fn cancel_order_rounding_test() -> anyhow::Result<()> {
+    let mut test_fixture: TestFixture = TestFixture::new().await;
+    test_fixture.claim_seat().await?;
+    test_fixture
+        .deposit(Token::USDC, 2 * USDC_UNIT_SIZE)
+        .await?;
+
+    test_fixture
+        .place_order(Side::Bid, 1, 11, -1, u32::MAX, OrderType::Limit)
+        .await?;
+
+    test_fixture.cancel_order(0).await?;
+    test_fixture
+        .withdraw(Token::USDC, 2 * USDC_UNIT_SIZE)
+        .await?;
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn cancel_order_fail_other_trader_order_test() -> anyhow::Result<()> {
     let mut test_fixture: TestFixture = TestFixture::new().await;