function greatestToLeast(array) {
  // your code goes here
  return array.sort(function(a, b){return b-a});
}






/* From here down, you are not expected to
   understand.... for now :)


   Nothing to see here!

*/


// tests

function testFunctionWorks(fn, input, expected) {
  const result = fn(input);
  if (
    result &&
    result.length === expected.length &&
    result.every(function(item, index) {
     return (index === 0 || result[index] < result[index-1]);
    }) &&
    result.every(function(item) {
      return expected.indexOf(item) > -1;
    })) {
    console.log('SUCCESS: `' + fn.name + '` works!')
    return true;
  }
  else {
    console.error('FAILURE: `' + fn.name + '([' + input + '])` should be ' + expected +
      ' but was ' + fn(input))
    return false;
  }
}

function runTests() {

  const input1 = [10, 3, 5, 22, 19];
  const result1 = [22, 19, 10, 5, 3];
  const input2 = [2, 4, 6, 8];
  const result2 = [8, 6, 4, 2];

  const testResults = [
    testFunctionWorks(greatestToLeast, input1, result1),
    testFunctionWorks(greatestToLeast, input2, result2),
  ];



  const numPassing = testResults.filter(function(result){ return result; }).length;
  console.log(numPassing + ' out of ' + testResults.length + ' tests passing.');
}

runTests();