function divisibleBy5(array) {
 return array.find(function(num) {
  return num % 5 === 0;
 });
}

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


   Nothing to see here!

*/

// tests

function testFunctionWorks(fn, input, expected) {
  if (fn(input) === expected) {
    console.log('SUCCESS: `' + fn.name + '` works on `[' + input + ']`');
    return true;
  } else {
    console.error(
      'FAILURE: `' +
        fn.name +
        '([' +
        input +
        '])` should be ' +
        expected +
        ' but was ' +
        fn(input)
    );
    return false;
  }
}

function runTests() {
  const input1 = [13, 22, 4, 47, 15, 35, 82];
  const result1 = 15;
  const input2 = [25, 20, 15, 10, 5];
  const result2 = 25;

  const testResults = [
    testFunctionWorks(divisibleBy5, input1, result1),
    testFunctionWorks(divisibleBy5, input2, result2),
  ];

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

runTests();