Add this into `ChristmasDinnerTest.t.sol`
Code:
```javascript
function testUserCanDepositeAfterDeadline() public {
vm.deal(user1, 10e18);
vm.warp(1 + 8 days);
vm.startPrank(user1);
(bool ok, ) = address(cd).call{value: 1e18}("");
vm.stopPrank();
assert(ok);
}
```
The `receive` frunction should be like
```diff
receive() external payable {
+ if(block.timestamp > deadline) {
+ revert BeyondDeadline()
+ }
etherBalance[msg.sender] += msg.value;
emit NewSignup(msg.sender, msg.value, true);
}
```