Fix reported bugbear: too broad exception assertion (#9753)

Author: anoadragon453

changelog.d/9753.misc

@@ -0,0 +1 @@
+Check that a `ConfigError` is raised, rather than simply `Exception`, when appropriate in homeserver config file generation tests.

tests/config/test_load.py

@@ -20,6 +20,7 @@
 
 import yaml
 
+from synapse.config import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 
 from tests import unittest
@@ -35,9 +36,9 @@ def tearDown(self):
 
     def test_load_fails_if_server_name_missing(self):
         self.generate_config_and_remove_lines_containing("server_name")
-        with self.assertRaises(Exception):
+        with self.assertRaises(ConfigError):
             HomeServerConfig.load_config("", ["-c", self.file])
-        with self.assertRaises(Exception):
+        with self.assertRaises(ConfigError):
             HomeServerConfig.load_or_generate_config("", ["-c", self.file])
 
     def test_generates_and_loads_macaroon_secret_key(self):