function testClientCanGetSignatureList()
{
$tk = parent::$testKeys;
$client = new PostmarkAdminClient($tk->WRITE_ACCOUNT_TOKEN, $tk->TEST_TIMEOUT);
$sigs = $client->listSenderSignatures();
$this->assertGreaterThan(0, $sigs->totalCount);
$this->assertNotEmpty($sigs->senderSignatures);
}