Add client's methods and testcases for tsigkey

Change-Id: I86cdf2b62f3586d35652891e4ace70ff8548640b
diff --git a/designate_tempest_plugin/data_utils.py b/designate_tempest_plugin/data_utils.py
index ae2b1a7..11113b8 100644
--- a/designate_tempest_plugin/data_utils.py
+++ b/designate_tempest_plugin/data_utils.py
@@ -233,3 +233,14 @@
         data['target_project_id'] = target_project_id
 
     return data
+
+
+def rand_tsig_algorithm():
+    algorithm = ['hmac-md5', 'hmac-sha1', 'hmac-sha224', 'hmac-sha256',
+                 'hmac-sha384', 'hmac-sha512']
+    return random.choice(algorithm)
+
+
+def rand_tsig_scope():
+    scope = ["ZONE", "POOL"]
+    return random.choice(scope)