Lesson 12 Fuzz test depositCollateral

[Mepsss]

I get this error when trying to do the first test using the Handler (03:57:08 in the 3rd video. https://youtu.be/wUjYK5gwNZs?t=14228 )

Thats my repository: https://github.com/Mepsss/foundry-simplified-DAI-f23

Thats the point where the test should fail ~50% of the time but mine always fails because of the insufficient allowance error.

meps@DESKTOP-3L4CA2N:~/foundry-f23/foundry-defi-stablecoin-f23$ forge test --match-test invariant_protocolMustHaveMoreValueThanTotalSupply
[⠔] Compiling...
No files changed, compilation skipped

Running 1 test for test/fuzz/Invariants.t.sol:Invariants
[FAIL. Reason: ERC20: insufficient allowance]
        [Sequence]
                sender=0x000000000000000000000000000000000000042a addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=failed():(bool), args=[]
                sender=0x0000000000000000000000000000000000000527 addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=failed():(bool), args=[]
                sender=0xf5a96da3858d4a76e31020817484c82d7eebda67 addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=depositCollateral(uint256,uint256), args=[471428386612561126165474702797 [4.714e29], 2]

 invariant_protocolMustHaveMoreValueThanTotalSupply() (runs: 1, calls: 3, reverts: 1)
Test result: FAILED. 0 passed; 1 failed; 0 skipped; finished in 8.47ms
Ran 1 test suites: 0 tests passed, 1 failed, 0 skipped (1 total tests)

Failing tests:
Encountered 1 failing test in test/fuzz/Invariants.t.sol:Invariants
[FAIL. Reason: ERC20: insufficient allowance]
        [Sequence]
                sender=0x000000000000000000000000000000000000042a addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=failed():(bool), args=[]
                sender=0x0000000000000000000000000000000000000527 addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=failed():(bool), args=[]
                sender=0xf5a96da3858d4a76e31020817484c82d7eebda67 addr=[test/fuzz/Handler.t.sol:Handler]0x2e234dae75c793f67a35089c9d99245e1c58470b calldata=depositCollateral(uint256,uint256), args=[471428386612561126165474702797 [4.714e29], 2]

 invariant_protocolMustHaveMoreValueThanTotalSupply() (runs: 1, calls: 3, reverts: 1)

Encountered a total of 1 failing tests, 0 tests succeeded

[usmanfarooq91]

You are missing couple of things in Handler::depositCollateral function.

First, in order to deposit collateral, msg.sender have to have the deposit amount in the first place. to get it do collateral.mint(msg.sender, amountCollateral);.

Second, msg.sender needs to approve the amountCollateral to DSCEngine so that it can be transferred to DSCEngine, do it like this collateral.approve(address(dsce), amountCollateral);

Third you need to prank approve and depositCollateral functions with msg.sender, do it like this

vm.startPrank(msg.sender);
collateral.approve(address(dsce), amountCollateral);
dsce.depositCollateral(address(collateral), amountCollateral);
vm.stopPrank();

After all the changes your depositCollateral function look like this

function depositCollateral(uint256 collateralSeed, uint256 amountCollateral) public {
        ERC20Mock collateral = _getCollateralFromSeed(collateralSeed);
        collateral.mint(msg.sender, amountCollateral);
        vm.startPrank(msg.sender);
        collateral.approve(address(dsce), amountCollateral);
        dsce.depositCollateral(address(collateral), amountCollateral);
        vm.stopPrank();
}

[Mepsss]

why didn't I see patrick do any of those in the video ? and it still worked

With your changes it does wotk tho, so thanks :D

[usmanfarooq91]

Few parts of the tutorial are out of sequence. It used to happen to me too when I was watching the tutorial.

[Mepsss]

ah ok, just making sure I didn't miss anything

[save-the-planet08]

Nice to have these information. I was stuck cause of this too.