[Ethereum] Truffle console.log is not working

you can delete your build directory and try again

rm -rf build
truffle compile
truffle migrate

oneliner

rm -rf build && truffle compile && truffle migrate

please try this:

contract("DappToken", function(accounts) {
    it("Token buying", function() {
        return DappToken.deployed().then(function (instance) {
            console.log(instance, 'instance');
        });
    });
});

This is my example in other smart contract, where the tests are running smoothly:

contract("CarData", function(accounts) {
    //setting up the account[1] will lead to revert, because account[1] is not allowed to call the method
    it('should revert the transaction of insertCarData when the from parameter is not the owner of the contract', function() {
        return CarData.deployed()
        .then(function (instance) {
            return instance.insertCarData("BG1234566", 1529767983, 1529767983, 1529767983, "1994", "Bulgaria", "Red", {from: accounts[0]});
        });
    });
});

It might be possible that console.logs are not showing when running the tests. Please try to run some method of your smart contract.