tests: disable pretty error page handler for tests, with option to

disable when testing error pages, fixes  #4208

rhodecode/config/environment.py

@@ -158,6 +158,8 b' def load_pyramid_environment(global_conf'
     # This has to be done before the database connection is initialized.
     if settings['is_test']:
         rhodecode.is_test = True
+        rhodecode.disable_error_handler = True
+
         utils.initialize_test_environment(settings_merged)
 
     # Initialize the database connection.

rhodecode/config/middleware.py

@@ -221,7 +221,8 b' def make_not_found_view(config):'
         except Exception as e:
             log.exception(e)
 
-            if settings.get('debugtoolbar.enabled', False):
+            if (settings.get('debugtoolbar.enabled', False) or
+                rhodecode.disable_error_handler):
                 raise
 
             if isinstance(e, VCSCommunicationError):

rhodecode/tests/lib/middleware/test_vcs_unavailable.py

@@ -20,6 +20,7 b''
 
 import mock
 import pytest
+import rhodecode
 import rhodecode.lib.vcs.client as client
 
 @pytest.mark.usefixtures('autologin_user', 'app')
@@ -34,9 +35,13 b' def test_vcs_available_returns_summary_p'
 def test_vcs_unavailable_returns_vcs_error_page(app, backend):
     url = '/{repo_name}'.format(repo_name=backend.repo.repo_name)
 
+    try:
+        rhodecode.disable_error_handler = False
     with mock.patch.object(client, '_get_proxy_method') as p:
         p.side_effect = client.exceptions.PyroVCSCommunicationError()
         response = app.get(url, expect_errors=True)
+    finally:
+        rhodecode.disable_error_handler = True
 
     assert response.status_code == 502
     assert 'Could not connect to VCS Server' in response.body