public function testProtectedApiGetNextSuffix_ReturnsNextSuffix()
{
$channel = $this->createChannel();
$cnt1 = $this->callProtectedMethod($channel, 'getNextSuffix');
$cnt2 = $this->callProtectedMethod($channel, 'getNextSuffix');
$cnt3 = $this->callProtectedMethod($channel, 'getNextSuffix');
$this->assertSame('1000000000', $cnt1);
$this->assertSame('1000000001', $cnt2);
$this->assertSame('1000000002', $cnt3);
}