Want to pass address of one contract into another inside Foundry test

I am working through OpenZeppelin's Ethernaut challenges and want to use Foundry. I have two smart contracts in my src folder:

• CoinFlip.sol (the challenge code) and
• CoinFlipBreak.sol (contract to solve the challenge)

In my test file in the setUp() function I want to instantiate the CoinFlip contract which is easy enough like so:

function setUp() public {
    coinFlip = new CoinFlip();
}

but after I do this I want to pass the address of the CoinFlip contract into the CoinFlipBreak contract. This does NOT work:

 coinFlipBreak = new CoinFlipBreak( coinFlip.address );

How can I get the address of the first contract passed in to the second?

Every contract is an address, and vice versa (when not EOA). And you can cast in both ways:

CoinFlip coinFlip = new CoinFlip();

// cast to address
address coinFlipAddress = address(coinFlip);

// cast to contract instance
CoinFlip coinFlipX = CoinFlip(coinFlipAddress)

An example with hardhat:

import "hardhat/console.sol";

contract A {

}
contract B {
    constructor (address addr) {
        A a = A(addr);
        console.log(address(a));
    }
}
contract Test {
    constructor () {
        A a = new A();
        B b = new B(address(a));
    }
}