PHP Version:
(lazy and dirty)

https://pastebin.com/q0GqCaG2

```
<?php

function fizzbuzz($n) {
  if (!($n % 3)) {
    $fizzbuzz .= 'Fizz';
  }
  if (!($n % 5)) {
    $fizzbuzz .= 'Buzz';
  }
  return $fizzbuzz;
}

for ($n = 0; $n <= 100; $n++) {
  echo $n . ': ';
  echo fizzbuzz($n);
  echo "\n";
}

function fizzbuzzTest() {
  echo (fizzbuzz(0) == 'FizzBuzz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(3) == 'Fizz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(6) == 'Fizz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(5) == 'Buzz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(10) == 'Buzz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(15) == 'FizzBuzz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(30) == 'FizzBuzz' ? 'passed' : 'failed') . "\n";
  echo (fizzbuzz(31) == '' ? 'passed' : 'failed') . "\n";
}

fizzbuzzTest();
```
#

I think most people will do 3 checks:

```
if %3 AND %5 ...
else if %3 ...
else if %5 ...
```

But

```
if %3 ...
if %5 ...
```

will have the same result when concatenating the strings.

You don't even have to handle n = 0 as a special case because strictly speaking 0 is a multiple of 3 and 5 because 3 * 0 is 0 and 5 * 0 is 0. Otherwise there's just another `if ($n)` missing.