feat(ldapobject): add asynchronous SASL bind support - #668

diff --git Tests/test_cext.py Tests/test_cext.py
index 4508fa5e..4c416877 100644
--- Tests/test_cext.py
+++ Tests/test_cext.py
@@ -833,6 +833,8 @@ class TestLdapCExtension(SlapdTestCase):
         self.check_invalid_controls(l.extop, 'oid', 'value')
         if hasattr(l, 'sasl_bind_s'):
             self.check_invalid_controls(l.sasl_bind_s, 'dn', 'MECH', 'CRED')
+        if hasattr(l, 'sasl_bind'):
+            self.check_invalid_controls(l.sasl_bind, 'dn', 'MECH', 'CRED')
         if hasattr(l, 'sasl_interactive_bind_s'):
             self.check_invalid_controls(l.sasl_interactive_bind_s, 'who', 'SASLObject', post=(1,))
         self.check_invalid_controls(l.unbind_ext)
diff --git Tests/test_ldap_sasl.py Tests/test_ldap_sasl.py
index d797807f..6f3b0ec6 100644
--- Tests/test_ldap_sasl.py
+++ Tests/test_ldap_sasl.py
@@ -73,6 +73,15 @@ class TestSasl(SlapdTestCase):
         ldap_conn.sasl_interactive_bind_s('', auth)
         assert ldap_conn.whoami_s().lower() == f'dn:{self.server.root_dn.lower()}'
 
+    @requires_ldapi()
+    def test_external_ldapi_async(self):
+        ldap_conn = self.ldap_object_class(self.server.ldapi_uri)
+
+        msgid = ldap_conn.sasl_bind('', 'EXTERNAL', '')
+        assert isinstance(msgid, int)
+        ldap_conn.result(msgid, all=1)
+        assert ldap_conn.whoami_s().lower() == f'dn:{self.server.root_dn.lower()}'
+
     @requires_tls()
     def test_external_tlscert(self):
         ldap_conn = self.ldap_object_class(self.server.ldap_uri)