Ability to withdraw 5% by default and up to 100% shares via DAO

Author: Usn Zorro

src/treasury/withdraw_stable_pool.rs

@@ -21,7 +21,7 @@ impl Contract {
     /// collateralization on the static accounts of USDT and USN contracts
     ///
     /// It fails if 'usn' is the only liquidity provider in the stable pool.
-    pub fn withdraw_stable_pool(&mut self) -> Promise {
+    pub fn withdraw_stable_pool(&mut self, percent: Option<u8>) -> Promise {
         self.assert_owner();
 
         let pool = Pool::stable_pool();
@@ -40,6 +40,7 @@ impl Contract {
             GAS_FOR_GET_SHARES,
         )
         .then(ext_self::handle_start_removing(
+            percent,
             env::current_account_id(),
             env::attached_deposit(),
             GAS_SURPLUS * 6
@@ -54,7 +55,7 @@ impl Contract {
 trait RefFinanceHandler {
     #[private]
     #[payable]
-    fn handle_start_removing(&mut self, #[callback] shares: U128) -> Promise;
+    fn handle_start_removing(&mut self, percent: Option<u8>, #[callback] shares: U128) -> Promise;
 
     #[private]
     #[payable]
@@ -65,7 +66,7 @@ trait RefFinanceHandler {
 }
 
 trait RefFinanceHandler {
-    fn handle_start_removing(&mut self, shares: U128) -> Promise;
+    fn handle_start_removing(&mut self, percent: Option<u8>, shares: U128) -> Promise;
 
     fn handle_remove_deposit(&mut self, amounts: Vec<U128>) -> Promise;
 
@@ -76,7 +77,7 @@ trait RefFinanceHandler {
 impl RefFinanceHandler for Contract {
     #[private]
     #[payable]
-    fn handle_start_removing(&mut self, #[callback] shares: U128) -> Promise {
+    fn handle_start_removing(&mut self, percent: Option<u8>, #[callback] shares: U128) -> Promise {
         let pool = Pool::stable_pool();
         let min_amounts = vec![U128(0), U128(0)];
 
@@ -86,8 +87,12 @@ impl RefFinanceHandler for Contract {
             "Requires exactly 3 yoctoNEAR of attached deposit"
         );
 
-        // 5% of shares
-        let shares_amount = U256::from(u128::from(shares)) * U256::from(5u128) / 100u128;
+        // 5% of shares by default, but 100% is maximum.
+        let percent = percent.unwrap_or(5);
+
+        require!(percent <= 100, "Maximum 100% of shares can be withdrawn");
+
+        let shares_amount = U256::from(u128::from(shares)) * U256::from(percent) / 100u128;
 
         ext_ref_finance::remove_liquidity(
             pool.id,

tests/tests.js

@@ -1450,24 +1450,107 @@ describe('Withdraw Stable Pool', async function () {
     );
   });
 
-  it('should remove stable liquidity', async () => {
-    // Clear wNEAR 'usn' account.
-    await global.wnearContract.burn({
-      args: {
-        account_id: config.usnId,
-        amount: await global.wnearContract.ft_balance_of({
-          account_id: config.usnId,
-        }),
+  it('should fail trying to withdraw 100% because there is only 1 participant', async () => {
+    await assert.rejects(
+      async () => {
+        await global.usnContract.withdraw_stable_pool({
+          args: { percent: 100 },
+          amount: 3 * ONE_YOCTO,
+          gas: GAS_FOR_CALL,
+        });
+      },
+      (err) => {
+        assert.match(err.message, /Callback computation 0 was not successful/);
+        return true;
+      }
+    );
+  });
+
+  it('should fail trying to withdraw 101% of liquidity', async () => {
+    await assert.rejects(
+      async () => {
+        await global.usnContract.withdraw_stable_pool({
+          args: { percent: 101 },
+          amount: 3 * ONE_YOCTO,
+          gas: GAS_FOR_CALL,
+        });
       },
+      (err) => {
+        assert.match(err.message, /Maximum 100%/);
+        return true;
+      }
+    );
+  });
+
+  it('should withdraw 99% of shares', async () => {
+    const poolInfoBefore = await global.refContract.get_stable_pool({
+      pool_id: 0,
+    });
+
+    await global.usnContract.withdraw_stable_pool({
+      args: { percent: 99 },
+      amount: 3 * ONE_YOCTO,
       gas: GAS_FOR_CALL,
     });
 
-    const wrapAmountBefore = await global.wnearContract.ft_balance_of({
+    const poolInfoAfter = await global.refContract.get_stable_pool({
+      pool_id: 0,
+    });
+
+    const usnDeposit = await global.refContract.get_deposit({
       account_id: config.usnId,
+      token_id: config.usnId,
+    });
+    const usdtDeposit = await global.refContract.get_deposit({
+      account_id: config.usnId,
+      token_id: config.usdtId,
     });
+    const wrapDeposit = await global.refContract.get_deposit({
+      account_id: config.usnId,
+      token_id: config.wnearId,
+    });
+    assert.equal(usnDeposit, '0');
+    assert.equal(usdtDeposit, '0');
+    assert.equal(wrapDeposit, '0');
+
+    assert(
+      new BN(poolInfoBefore.amounts[0]).gt(new BN(poolInfoAfter.amounts[0]))
+    );
 
-    assert.equal(wrapAmountBefore, '0');
+    assert(
+      new BN(poolInfoBefore.amounts[1]).gt(new BN(poolInfoAfter.amounts[1]))
+    );
 
+    const poolUsn99Percent = new BN(poolInfoBefore.amounts[0])
+      .mul(new BN(991))
+      .div(new BN(1000));
+    const poolUsn98Percent = new BN(poolInfoBefore.amounts[0])
+      .mul(new BN(98))
+      .div(new BN(100));
+    const usnAmountDiff = new BN(poolInfoBefore.amounts[0]).sub(
+      new BN(poolInfoAfter.amounts[0])
+    );
+
+    // Withdrawn 98% < USN < 99%
+    assert(usnAmountDiff.gt(new BN(poolUsn98Percent)));
+    assert(usnAmountDiff.lt(new BN(poolUsn99Percent)));
+
+    const poolUsdt99Percent = new BN(poolInfoBefore.amounts[1])
+      .mul(new BN(991))
+      .div(new BN(1000));
+    const poolUsdt98Percent = new BN(poolInfoBefore.amounts[1])
+      .mul(new BN(98))
+      .div(new BN(100));
+    const usdtAmountDiff = new BN(poolInfoBefore.amounts[1]).sub(
+      new BN(poolInfoAfter.amounts[1])
+    );
+
+    // Withdrawn 98% < USDT < 99%
+    assert(usdtAmountDiff.gt(new BN(poolUsdt98Percent)));
+    assert(usdtAmountDiff.lt(new BN(poolUsdt99Percent)));
+  });
+
+  it('should withdraw 5% of shares', async () => {
     const poolInfoBefore = await global.refContract.get_stable_pool({
       pool_id: 0,
     });
@@ -1494,14 +1577,9 @@ describe('Withdraw Stable Pool', async function () {
       account_id: config.usnId,
       token_id: config.wnearId,
     });
-    const wrapAmount = await global.wnearContract.ft_balance_of({
-      account_id: config.usnId,
-    });
-
     assert.equal(usnDeposit, '0');
     assert.equal(usdtDeposit, '0');
     assert.equal(wrapDeposit, '0');
-    assert.equal(wrapAmount, '0');
 
     assert(
       new BN(poolInfoBefore.amounts[0]).gt(new BN(poolInfoAfter.amounts[0]))