Add tests for mattermost login via oauth

* Adds Runtime::Scenario as a place to record the properties of the
  Scenario we're interested in.

* Adds a positional argument to Test::Integration::Mattermost to specify
  Runtime::Scenario.mattermost

* Adds Page::Mattermost::{Main,Login} to model the mattermost pages we
  need to interact with.

* Adds qa/features/mattermost/login_spec to perform a login via oauth
  and ensure we are logged in.

2 files changed, 30 insertions, 0 deletions

diff --git a/qa/qa/page/mattermost/login.rb b/qa/qa/page/mattermost/login.rb
new file mode 100644
index 00000000000..2001dc5b230
--- /dev/null
+++ b/qa/qa/page/mattermost/login.rb
@@ -0,0 +1,19 @@
+module QA
+  module Page
+    module Mattermost
+      class Login < Page::Base
+        def initialize
+          visit(Runtime::Scenario.mattermost + '/login')
+        end
+
+        def sign_in_using_oauth
+          click_link class: 'btn btn-custom-login gitlab'
+
+          if page.has_content?('Authorize GitLab Mattermost to use your account?')
+            click_button 'Authorize'
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/qa/qa/page/mattermost/main.rb b/qa/qa/page/mattermost/main.rb
new file mode 100644
index 00000000000..e636d7676f4
--- /dev/null
+++ b/qa/qa/page/mattermost/main.rb
@@ -0,0 +1,11 @@
+module QA
+  module Page
+    module Mattermost
+      class Main < Page::Base
+        def initialize
+          visit(Runtime::Scenario.mattermost)
+        end
+      end
+    end
+  end
+end