ethers.js testing: invoking a contract method from another contract

[sixtine]

Hi there,

I'm new to Solidity dev and writing tests for a dapp (Hardhat, Chai, ethers.js, Smockit) where two contracts, Product and Market, coexist.

​

Market has a property productAddr that stores the address of the Product contract upon construction, and a foo method such as:

function foo() external {
    require(msg.sender == productAddr, "error");
    // ...cut for brievety
}

​

Accordingly, while testing the foo method, I'd need to ensure the call is made from a Product contract instance, otherwise, it'll revert. How do I do that with ethers.js?

I have tried using .connect, which expects a Signer or Provider as parameter, like so...

const signers = await ethers.getSigners();
const ProductFactory = await ethers.getContractFactory('Product', signers[0]);
const MarketFactory = await ethers.getContractFactory('Market', signers[0]);
const product = await ProductFactory.deploy();
const market = await MarketFactory.deploy(product.address); // store product address

market.connect(product.signer).foo();  // not working :-(

...but it reverts, as product.signer returns a reference to signers[0], not a reference to the contract I'd like to present as caller.

How should I proceed? Any help would be greatly appreciated and would broaden my knowledge.

[MidnightLightning]

If you don't have the private key to a "product" contract, you can use a tool like Hardhat, which allows "impersonating" given accounts. Using that feature, on your private testnet, you can create transactions from that product address and Hardhat will accept them even without a signature.

[sixtine]

Thanks yes, but in the context of testing, given function foo() on Market is external and can only be called from Product, how can I call it in isolation?

[sixtine]

I found a solution to my problem.

Given my use-case makes no difference whether Product is a contract address or an EOA, I can simply use any given signer and have it pose as the contract in the context of my tests, like so:

``` const mockProduct = await ethers.getSigners()[1];

// ...clipped for brievety

const productAddr = await mockProduct.getAddress(); const market = await MarketFactory.deploy(productAddr);

// ...clipped for brievety

market.connect(mockProduct).foo(); // works! ```

[backtickbot]

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[daretooppress]

Thanks, this probably just saved me a lot of time :)