public static function _default_credentials()
 {
     return CredentialProvider::resolve(CredentialProvider::defaultProvider());
 }
 public function testCallsDefaultsCreds()
 {
     $u = getenv(CredentialProvider::ENV_USERNAME);
     $p = getenv(CredentialProvider::ENV_PASSWORD);
     $s = getenv(CredentialProvider::ENV_SUBSCRIPTION_TOKEN);
     putenv(CredentialProvider::ENV_USERNAME . '=abc');
     putenv(CredentialProvider::ENV_PASSWORD . '=123');
     putenv(CredentialProvider::ENV_SUBSCRIPTION_TOKEN . '=1to2ken3');
     $provider = CredentialProvider::defaultProvider();
     $creds = $provider();
     putenv(CredentialProvider::ENV_USERNAME . "={$u}");
     putenv(CredentialProvider::ENV_PASSWORD . "={$p}");
     putenv(CredentialProvider::ENV_SUBSCRIPTION_TOKEN . "={$s}");
     $this->assertEquals('abc', $creds->getUsername());
     $this->assertEquals('123', $creds->getPassword());
     $this->assertEquals('1to2ken3', $creds->getSubscriptionToken());
 }