public function testCoprime()
{
$a = '14';
$b = '21';
$math = new BcEngine();
$this->assertFalse($math->coprime($a, $b));
$a = '1';
$b = '-1';
$math = new BcEngine();
$this->assertTrue($math->coprime($a, $b));
$a = '14';
$b = '15';
$math = new BcEngine();
$this->assertTrue($math->coprime($a, $b));
}
