How to Properly Unit Test onlyOwner

Question

My contract inherits the ownable.sol which has a mint() method that is marked onlyOwner like below:

 function mint(address _to, string memory newTokenURI) public onlyOwner 

I know that within the ownable if the owner check fails it would return a rejected message "Ownable: caller is not the owner". I am trying to test my mint function's user access to do full test coverage. Note: I am using the chai-matchers library

describe("EFTContract", function () {
  let token721;
  let TEST_URI1 = "ipfs://tokenurifor1";
  beforeEach(async function () {
    EFT721Contract = await ethers.getContractFactory("EFTNFT");
    [owner, account1, ...otheraccounts] = await ethers.getSigners();
    token721 = await EFT721Contract .deploy();
  });

  
  describe("Ownership Tests", function () {
    // ok
    it("Testowner can call mint()", async function () {
      expect(await token721.mint(account1.address, TEST_URI1)).to.not.be.reverted;
    });
    // fails
    it("Test guest should not call mint()", async function () {
      // mint 1 so we have a valid token to try to query with tokenURI()
      await token721.mint(account1.address, TEST_URI1);
      // connect to guest account to try and mint
      await expect(token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .to.be.rejectedWith("Ownable: caller is not the owner");
    });'
  });

When I run this the first test passes but the second fails with the following error:

"VoidSigner cannot sign transactions (operation=\"signTransaction\", code=UNSUPPORTED_OPERATION, version=abstract-signer/5.6.2)"

I know I can replace that assert to pass the test replacing it with the code below but I believe that isnt properly testing ownership access of the ownable.sol contract:

 await expect(token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .eventually.to.rejectedWith(Error, "VoidSigner cannot sign transactions (operation=\"signTransaction\", code=UNSUPPORTED_OPERATION, version=abstract-signer/5.6.2)");

How can I instead modify the second test case to properly compare against `"Ownable: caller is not the owner"?

Solution: It looks like I should wait for the promise to resolve before comparing the results. In this case it would provide an error instead of a rejected messaged so I should use .to.be.revertedWith() instead.

    // mint
    it("Testowner can call mint()", async function () {
      expect(await token721.mint(account1.address, TEST_URI1)).to.not.be.reverted;
    });

    it("Test guest should not call mint()", async function () {
      await expect(token721
        .connect(account1)
        .mint(account1.address, TEST_URI1))
        .to.be.revertedWith("Ownable: caller is not the owner");
    });

Answer 1

The await keyword is at the wrong place. Replace this part:

      await expect(token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .to.be.rejectedWith("Ownable: caller is not the owner");

Like this:

      expect(await token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .to.be.rejectedWith("Ownable: caller is not the owner");

Make sure to execute the expect() after the await.

Update: It's also because you're connecting to the account the wrong way. Don't do this:

.connect(account1.address)

Do this:

.connect(account1)

Answer 2

I don't know if @Merunas G's answer was on a different version of Hardhat Ethers (*), but moving the await didn't work for me. This should work (note the use of reverted as was discussed in @Merunas's answer's comments):

await expect(token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .to.be.revertedWith("Ownable: caller is not the owner");

However, the Ownable abstract contract uses a Custom Error (https://hardhat.org/hardhat-chai-matchers/docs/overview#reverts) so the answer (at least today - *) is:

await expect(token721
        .connect(account1.address)
        .mint(account1.address, TEST_URI1))
        .to.be.revertedWithCustomError(token721, "OwnableUnauthorizedAccount");

• • ethers6 introduced a lot of breaking changes