Add cross-source tests

Change-Id: Iaf31211d12a2c8ce3b4a2860e079748f7e705aba
Story: 2001334
Task: 5885
diff --git a/tests/fixtures/zuul-gerrit-github.conf b/tests/fixtures/zuul-gerrit-github.conf
new file mode 100644
index 0000000..d3cbf7b
--- /dev/null
+++ b/tests/fixtures/zuul-gerrit-github.conf
@@ -0,0 +1,35 @@
+[gearman]
+server=127.0.0.1
+
+[statsd]
+# note, use 127.0.0.1 rather than localhost to avoid getting ipv6
+# see: https://github.com/jsocol/pystatsd/issues/61
+server=127.0.0.1
+
+[scheduler]
+tenant_config=main.yaml
+
+[merger]
+git_dir=/tmp/zuul-test/merger-git
+git_user_email=zuul@example.com
+git_user_name=zuul
+
+[executor]
+git_dir=/tmp/zuul-test/executor-git
+
+[connection gerrit]
+driver=gerrit
+server=review.example.com
+user=jenkins
+sshkey=fake_id_rsa_path
+
+[connection github]
+driver=github
+webhook_token=0000000000000000000000000000000000000000
+
+[connection smtp]
+driver=smtp
+server=localhost
+port=25
+default_from=zuul@example.com
+default_to=you@example.com