Tests: removed TestApplicationTLS.get_server_certificate().

distutils.version is replaced by packaging.version.  Also minor style fixes.

test/test_variables.py

@@ -103,20 +103,16 @@ class TestVariables(TestApplicationProto):
     def test_variables_empty(self):
         def update_pass(prefix):
             assert 'success' in self.conf(
-                {
-                    "listeners": {
-                        "*:7080": {"pass": prefix + "/$method"},
-                    },
-                },
+                {"listeners": {"*:7080": {"pass": prefix + "/$method"}}},
             ), 'variables empty'
 
-        update_pass("routes");
+        update_pass("routes")
         assert self.get(url='/1')['status'] == 404
 
-        update_pass("upstreams");
+        update_pass("upstreams")
         assert self.get(url='/2')['status'] == 404
 
-        update_pass("applications");
+        update_pass("applications")
         assert self.get(url='/3')['status'] == 404
 
     def test_variables_invalid(self):