Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.4.25+commit.59dbf8f1.js&optimize=true&gist=

ballot.sol

pragma solidity ^0.4.0;

// import ""

contract Test {
    int a =10;
    int b = 15;

    function add(a,  b )public constant returns(int) {
        return a+b;
    }
}

ballot_test.sol

pragma solidity ^0.4.7;
import "remix_tests.sol"; // this import is automatically injected by Remix.
import "./ballot.sol";

contract test3 {
   
    Ballot ballotToTest;
    function beforeAll () {
       ballotToTest = new Ballot(2);
    }
    
    function checkWinningProposal () public {
        ballotToTest.vote(1);
        Assert.equal(ballotToTest.winningProposal(), uint(1), "1 should be the winning proposal");
    }
    
    function checkWinninProposalWithReturnValue () public constant returns (bool) {
        return ballotToTest.winningProposal() == 1;
    }
}

test1.sol

pragma solidity ^0.4.0;

// import ""

contract Test {
    int a =10;
    int b = 15;

    function add()public constant returns(int) {
        return a+b;
    }
}

testAddr.sol

pragma solidity ^0.4.16;

contract ArrayTest {
    uint[] public u = [1,2,3,4];

    string s = "12345678";

    function h() public constant returns (uint) {
        return bytes(s).length;
    }

    function f() public view returns (byte){
        return bytes(s)[3];
    }
}