//Unit Test starts
  it("MasterChef - Zero Concur balance", async function() {
    await concurToken.mint(masterChef.address, 100);
    console.log(await concurToken.balanceOf(masterChef.address), await concurToken.balanceOf(user1.address));
    await masterChef.safeConcurTransfer(user1.address, 60); // user1 is rewarded correctly.
    console.log(await concurToken.balanceOf(masterChef.address), await concurToken.balanceOf(user1.address));
    await masterChef.safeConcurTransfer(user1.address, 60); // user1 is rewarded lesser by 10.
    console.log(await concurToken.balanceOf(masterChef.address), await concurToken.balanceOf(user1.address));
    await masterChef.safeConcurTransfer(user1.address, 60); // user1 is totally not rewarded.
    console.log(await concurToken.balanceOf(masterChef.address), await concurToken.balanceOf(user1.address));
  });
//Unit Test ends
    function safeConcurTransfer(address _to, uint _amount) private {
        uint concurBalance = concur.balanceOf(address(this));
        require(concurBalance>0, "safeConcurTransfer: balance is zero.");
