How do I test burning tokens?

[kihiuFrank]

I'm writing tests for the burn func

The first two tests are passing, but when I come to test where the tokens are indeed burned, the state of the ICO seems to change. To burn tokens, the ICO must have ended. So I start by checking the ICO state, and up to that point, the state is ended. When I call await ico.burn() the state seems to change and I get the error below.

What could I be doing wrong?

error

 Error: VM Exception while processing transaction: reverted with custom error 'Ico__StateShouldBeEnded()'

burn() func

    function burn() public onlyManager returns (bool) {
        icoState = getState();
        // require(icoState == State.afterEnd);
        if (icoState != State.afterEnd) {
            revert Ico__StateShouldBeEnded();
        }
        //burn
        balances[founder] = 0;
        return true;
    }

test file

describe("burning tokens", () => {
              it("checks that the ico is ended before burning", async () => {
                  const icoState = await ico.getState()
                  assert.equal(icoState, 1) // state [1] = afterEnd on our ICO.sol
              })

              it("only allows manager to call", async () => {
                  const icoInvestor1connected = ico.connect(inverstor1)
                  await expect(icoInvestor1connected.burn()).to.be.rejectedWith("not owner")
              })

              it("should burn tokens", async () => {
                  const icoState = await ico.getState()
                  assert.equal(icoState, 1) // state [1] = afterEnd on our ICO.sol
                  
                  // up to this point the test passes. 
                  // it fails from the code below.

                  await ico.burn()
                  const founderBal = await ico.getFounderBalance()
                  assert.equal(founderBal.toString(), "0")
              })
          })

Repo

https://github.com/kihiuFrank/ICO