From 9e40d4ed4f0e67366646f3dea00292636b18db59 Mon Sep 17 00:00:00 2001
From: Uncle Fatso <uncle.fatso@ghostchain.io>
Date: Fri, 27 Jun 2025 21:39:38 +0300
Subject: [PATCH] tests of the burning functionality

Signed-off-by: Uncle Fatso <uncle.fatso@ghostchain.io>
---
 src/mocks/Reserve.sol     |   2 +-
 test/tokens/Reserve.t.sol | 104 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/src/mocks/Reserve.sol b/src/mocks/Reserve.sol
index 52a8d1e..dd1cf81 100644
--- a/src/mocks/Reserve.sol
+++ b/src/mocks/Reserve.sol
@@ -57,7 +57,7 @@ contract Reserve is ERC20Permit {
         _mint(account, msg.value * conversionRate);
     }
 
-    function burn(uint256 amount) external payable {
+    function burn(uint256 amount) external {
         _burn(msg.sender, amount);
         uint256 valueDiff = address(this).balance - accumulatedDonation;
         uint256 valueBack = amount * valueDiff / (amount + totalSupply());
diff --git a/test/tokens/Reserve.t.sol b/test/tokens/Reserve.t.sol
index daa949f..bd3a613 100644
--- a/test/tokens/Reserve.t.sol
+++ b/test/tokens/Reserve.t.sol
@@ -150,6 +150,28 @@ contract ReserveTest is Test {
         assertEq(faucetAddress.balance, sendAmount);
     }
 
+    function test_withdraw_onlyAccumulatedDonationsCouldBeWithdrawn() public {
+        assertEq(address(reserve).balance, 0);
+        vm.prank(initializer);
+        reserve.changeDonationRate(5 * 1e4); // 50%
+
+        deal(aliceAddress, sendAmount);
+        vm.prank(aliceAddress);
+        reserve.mint{ value: sendAmount }(aliceAddress);
+
+        assertEq(address(reserve).balance, sendAmount);
+
+        vm.prank(initializer);
+        reserve.withdraw(payable(faucetAddress));
+        assertEq(address(reserve).balance, sendAmount / 2);
+        assertEq(faucetAddress.balance, sendAmount / 2);
+
+        vm.prank(initializer);
+        reserve.withdraw(payable(faucetAddress));
+        assertEq(address(reserve).balance, sendAmount / 2);
+        assertEq(faucetAddress.balance, sendAmount / 2);
+    }
+
     function test_withdraw_couldNotBeDoneByArbitraryAddress() public {
         assertEq(address(reserve).balance, 0);
 
@@ -166,4 +188,86 @@ contract ReserveTest is Test {
         assertEq(address(reserve).balance, sendAmount);
         assertEq(aliceAddress.balance, 0);
     }
+
+    function test_burn_shouldReturnFullAmountIfRateNotSet() public {
+        deal(aliceAddress, sendAmount);
+        vm.prank(aliceAddress);
+        reserve.mint{ value: sendAmount }(aliceAddress);
+
+        uint256 balance = reserve.balanceOf(aliceAddress);
+        assertEq(reserve.totalSupply(), sendAmount * conversionRate);
+        assertEq(reserve.totalSupply(), balance);
+        assertEq(reserve.accumulatedDonation(), 0);
+        assertEq(aliceAddress.balance, 0);
+
+        vm.prank(aliceAddress);
+        reserve.burn(balance);
+
+        assertEq(reserve.totalSupply(), 0);
+        assertEq(reserve.balanceOf(aliceAddress), 0);
+        assertEq(reserve.accumulatedDonation(), 0);
+        assertEq(aliceAddress.balance, sendAmount);
+    }
+
+    function test_burn_shouldTakeDonationInAccordanceToRate() public {
+        vm.prank(initializer);
+        reserve.changeDonationRate(5 * 1e4); // 50%
+
+        deal(aliceAddress, sendAmount);
+        vm.prank(aliceAddress);
+        reserve.mint{ value: sendAmount }(aliceAddress);
+
+        uint256 balance = reserve.balanceOf(aliceAddress);
+        assertEq(reserve.totalSupply(), sendAmount * conversionRate);
+        assertEq(reserve.totalSupply(), balance);
+        assertEq(reserve.accumulatedDonation(), sendAmount / 2);
+        assertEq(aliceAddress.balance, 0);
+
+        vm.prank(aliceAddress);
+        reserve.burn(balance);
+
+        assertEq(reserve.totalSupply(), 0);
+        assertEq(reserve.balanceOf(aliceAddress), 0);
+        assertEq(reserve.accumulatedDonation(), sendAmount / 2);
+        assertEq(aliceAddress.balance, sendAmount / 2);
+    }
+
+    function test_burn_multipleUsersAccumulateInTotal() public {
+        vm.prank(initializer);
+        reserve.changeDonationRate(5 * 1e4); // 50%
+
+        deal(aliceAddress, sendAmount);
+        vm.prank(aliceAddress);
+        reserve.mint{ value: sendAmount }(aliceAddress);
+
+        vm.prank(initializer);
+        reserve.changeRate(conversionRate * 9);
+
+        deal(bobAddress, sendAmount);
+        vm.prank(bobAddress);
+        reserve.mint{ value: sendAmount }(bobAddress);
+
+        assertEq(aliceAddress.balance, 0);
+        assertEq(bobAddress.balance, 0);
+        uint256 aliceBalance = reserve.balanceOf(aliceAddress);
+        uint256 bobBalance = reserve.balanceOf(bobAddress);
+
+        uint256 bobEstimation = reserve.estimateAmount(bobBalance);
+        uint256 aliceEstimation = reserve.estimateAmount(aliceBalance);
+
+        vm.prank(bobAddress);
+        reserve.burn(bobBalance);
+
+        vm.prank(aliceAddress);
+        reserve.burn(aliceBalance);
+
+        assertEq(bobAddress.balance, sendAmount * 9 / 10);
+        assertEq(bobAddress.balance, bobEstimation);
+        assertEq(aliceAddress.balance, sendAmount / 10);
+        assertEq(aliceAddress.balance, aliceEstimation);
+
+        assertEq(reserve.totalSupply(), 0);
+        assertEq(reserve.accumulatedDonation(), sendAmount);
+        assertEq(address(reserve).balance, sendAmount);
+    }
 }