_Follow along with this video:_ --- ### First failed test Let's continue writing tests for our `FundMe` contract. Let's test if the owner (which should be us) is recorded properly. Add the following function to your testing file: ```javascript function testOwnerIsMsgSender() public { assertEq(fundMe.i_owner(), msg.sender); } ``` Run it via `forge test`. Output: ``` Ran 2 tests for test/FundMe.t.sol:FundMeTest [PASS] testMinimumDollarIsFive() (gas: 5453) [FAIL. Reason: assertion failed] testOwnerIsMsgSender() (gas: 22521) Suite result: FAILED. 1 passed; 1 failed; 0 skipped; finished in 3.85ms (623.00µs CPU time) Ran 1 test suite in 367.24ms (3.85ms CPU time): 1 tests passed, 1 failed, 0 skipped (2 total tests) Failing tests: Encountered 1 failing test in test/FundMe.t.sol:FundMeTest [FAIL. Reason: assertion failed] testOwnerIsMsgSender() (gas: 22521) ``` So ... why did it fail? Didn't we call the `new FundMe();` to deploy, making us the owner? We can find the answer to these questions in various ways, in the last lesson we learned about `console.log`, let's add some `console.log`s to see more information about the two elements of the assertion. ```javascript function testOwnerIsMsgSender() public { console.log(fundMe.i_owner()); console.log(msg.sender); assertEq(fundMe.i_owner(), msg.sender); } ``` Let's run `forge test -vv`: ``` Ran 2 tests for test/FundMe.t.sol:FundMeTest [PASS] testMinimumDollarIsFive() (gas: 5453) [FAIL. Reason: assertion failed] testOwnerIsMsgSender() (gas: 26680) Logs: 0x7FA9385bE102ac3EAc297483Dd6233D62b3e1496 0x1804c8AB1F12E6bbf3894d4083f33e07309d1f38 Error: a == b not satisfied [address] Left: 0x7FA9385bE102ac3EAc297483Dd6233D62b3e1496 Right: 0x1804c8AB1F12E6bbf3894d4083f33e07309d1f38 Suite result: FAILED. 1 passed; 1 failed; 0 skipped; finished in 975.40µs (449.20µs CPU time) Ran 1 test suite in 301.60ms (975.40µs CPU time): 1 tests passed, 1 failed, 0 skipped (2 total tests) Failing tests: Encountered 1 failing test in test/FundMe.t.sol:FundMeTest [FAIL. Reason: assertion failed] testOwnerIsMsgSender() (gas: 26680) ``` Ok, so the addresses are different, but why? Technically we are not the ones that deployed the `FundMe` contract. The `FundMe` contract was deployed by the `setUp` function, which is part of the `FundMeTest` contract. So, even though we are the ones who called `setUp` via `forge test`, the actual testing contract is the deployer of the `FundMe` contract. To test the above let's tweak the `testOwnerIsMsgSender` function: ```javascript function testOwnerIsMsgSender() public { assertEq(fundMe.i_owner(), address(this)); } ``` Run `forge test`. It passes! Congratulations! Feel free to try and write other tests!