chore: pytestify auth model (#1705)

* fix: black ci errors

* chore: pytestify auth model

---------

Co-authored-by: Jordan Woods <[email protected]>

Author: jorwoods

test/test_tableauauth_model.py

@@ -1,12 +1,8 @@
-import unittest
+import pytest
 
 import tableauserverclient as TSC
 
 
-class TableauAuthModelTests(unittest.TestCase):
-    def setUp(self):
-        self.auth = TSC.TableauAuth("user", "password", site_id="site1", user_id_to_impersonate="admin")
-
-    def test_username_password_required(self):
-        with self.assertRaises(TypeError):
-            TSC.TableauAuth()
+def test_username_password_required():
+    with pytest.raises(TypeError):
+        TSC.TableauAuth()