_Follow along with the video_ --- ### Introduction In this lesson we are going to build a couple more tests. If we check our code coverage with `forge coverage`, the terminal will show that we are only at around 53% coverage for the `Raffle.sol` contract. Code coverage refers to the percentage of lines of code that have been tested. > 💡 **TIP**:br > Achieving 100% coverage isn't always required, but it is a recommended target. ### `checkUpkeep` tests To improve our coverage, we need to write additional tests. For example we can address the `checkUpkeep` function, to ensure it really executes as intended under various circumstances. 1. Let’s start by ensuring that `checkUpkeep` returns `false` when there is no balance. We’ll do this by setting up our test environment similarly to previous tests but without entering the raffle. Here’s the code: ```solidity function testCheckUpkeepReturnsFalseIfItHasNoBalance() public { // Arrange vm.warp(block.timestamp + automationUpdateInterval + 1); vm.roll(block.number + 1); // Act (bool upkeepNeeded,) = raffle.checkUpkeep(""); // Assert assert(!upkeepNeeded); } ``` 2. Next, we want to assert that `checkUpkeep` returns `false` when the raffle is in a _not open_ state. To do this, we can use a setup similar to our previous test: ```solidity function testCheckUpkeepReturnsFalseIfRaffleIsntOpen() public { // Arrange vm.prank(PLAYER); raffle.enterRaffle{value: raffleEntranceFee}(); vm.warp(block.timestamp + automationUpdateInterval + 1); vm.roll(block.number + 1); raffle.performUpkeep(""); Raffle.RaffleState raffleState = raffle.getRaffleState(); // Act (bool upkeepNeeded,) = raffle.checkUpkeep(""); // Assert assert(raffleState == Raffle.RaffleState.CALCULATING); assert(upkeepNeeded == false); } ``` ### Conclusion By writing these additional tests, we enhance our test coverage rate, improve the reliability of our `Raffle.sol` contract, and check that `checkUpkeep` behaves correctly under various conditions.