A simple Solidity Contract for testing.

Counter.sol

pragma solidity 0.4.24;

contract Counter {
    
    int private count = 0;
    event counterIncremented(int indexed cnt, uint _time);
    event counterDecremented(int indexed cnt, uint _time);
    
    function incrementCounter() public {
        count += 1;
        emit counterIncremented(count, now);
    }
    function decrementCounter() public {
        count -= 1;
        emit counterDecremented(count, now);
    }
    function getCount() public view returns (int) {
        return count;
    }
    
}