self = <ipatests.test_integration.test_caless.TestServerInstall object at 0x7fb732e07e10>

    def test_nonexistent_ca_pem_file(self):
        "IPA server install with non-existent CA PEM file "

        self.export_pkcs12('ca1/server')
        with open(self.pem_filename, 'w') as f:
>           f.write(self.get_pem('ca2'))
E           TypeError: expected a string or other character buffer object

test_integration/test_caless.py:338: TypeError