function test_printPingWhenDivisibleByThree()
{
//Arrange
$test_PingPongGenerator = new PingPongGenerator();
$input = 11;
//Act
$result = $test_PingPongGenerator->generatePingArray($input);
//Assert
$this->assertEquals(array(1, 2, "ping", 4, 5, "ping", 7, 8, "ping", 10, 11), $result);
}
