text: // Given an array of integers, function will find the 
  // one that appears an odd number of times.
  // There will always be only one integer that appears 
  // an odd number of times.
  function findOdd(A) {
    const countObj = {};
    
    A.forEach((num) => {
      if (countObj[num]) {
        countObj[num]++;
      } else {
        countObj[num] = 1;
      }
    });
    
    let odd_num;
    for (let num in countObj) {
      if (countObj[num] % 2 === 1) {
        odd_num = num;
        break;
      }
    }
    return Number(odd_num);
  }
  
  
  function doTest(a, n) {
    console.log("A = ", a);
    console.log("n = ", n);
    Test.assertEquals(findOdd(a), n);
  }
  
  Test.describe('Example tests', function() {
    doTest([20,1,-1,2,-2,3,3,5,5,1,2,4,20,4,-1,-2,5], 5);
    doTest([1,1,2,-2,5,2,4,4,-1,-2,5], -1);
    doTest([20,1,1,2,2,3,3,5,5,4,20,4,5], 5);
    doTest([10], 10);
    doTest([1,1,1,1,1,1,10,1,1,1,1], 10);
    doTest([5,4,3,2,1,5,4,3,2,10,10], 1);
  });