public function testSetAmount()
{
$this->tx->setAmount(999.99);
$this->assertNotNull($this->tx->getAmount());
$this->assertSame($this->tx->getAmount(), 999.99);
$this->tx->setAmount('999.99');
$this->assertNotNull($this->tx->getAmount());
$this->assertSame($this->tx->getAmount(), '999.99');
}