Make Omniauth providers specs to not modify global configuration

CHANGELOG

@@ -36,6 +36,7 @@ v 8.9.0 (unreleased)
   - Use downcased path to container repository as this is expected path by Docker
   - Projects pending deletion will render a 404 page
   - Measure queue duration between gitlab-workhorse and Rails
+  - Make Omniauth providers specs to not modify global configuration
   - Make authentication service for Container Registry to be compatible with < Docker 1.11
   - Add Application Setting to configure Container Registry token expire delay (default 5min)
   - Cache assigned issue and merge request counts in sidebar nav

spec/controllers/import/import_spec_helper.rb

@@ -28,6 +28,6 @@ module ImportSpecHelper
       app_id: 'asd123',
       app_secret: 'asd123'
     )
-    Gitlab.config.omniauth.providers << provider
+    allow(Gitlab.config.omniauth).to receive(:providers).and_return([provider])
   end
 end

spec/lib/gitlab/bitbucket_import/client_spec.rb

 require 'spec_helper'
 
 describe Gitlab::BitbucketImport::Client, lib: true do
+  include ImportSpecHelper
+
   let(:token) { '123456' }
   let(:secret) { 'secret' }
   let(:client) { Gitlab::BitbucketImport::Client.new(token, secret) }
 
   before do
-    Gitlab.config.omniauth.providers << OpenStruct.new(app_id: "asd123", app_secret: "asd123", name: "bitbucket")
+    stub_omniauth_provider('bitbucket')
   end
 
   it 'all OAuth client options are symbols' do

spec/lib/gitlab/bitbucket_import/importer_spec.rb

 require 'spec_helper'
 
 describe Gitlab::BitbucketImport::Importer, lib: true do
+  include ImportSpecHelper
+
   before do
-    Gitlab.config.omniauth.providers << OpenStruct.new(app_id: "asd123", app_secret: "asd123", name: "bitbucket")
+    stub_omniauth_provider('bitbucket')
   end
 
   let(:statuses) do

spec/lib/gitlab/gitlab_import/client_spec.rb

 require 'spec_helper'
 
 describe Gitlab::GitlabImport::Client, lib: true do
+  include ImportSpecHelper
+
   let(:token) { '123456' }
   let(:client) { Gitlab::GitlabImport::Client.new(token) }
 
   before do
-    Gitlab.config.omniauth.providers << OpenStruct.new(app_id: "asd123", app_secret: "asd123", name: "gitlab")
+    stub_omniauth_provider('gitlab')
   end
 
   it 'all OAuth2 client options are symbols' do

spec/services/projects/import_service_spec.rb

@@ -124,7 +124,7 @@ describe Projects::ImportService, services: true do
         }
       )
 
-      Gitlab.config.omniauth.providers << provider
+      allow(Gitlab.config.omniauth).to receive(:providers).and_return([provider])
     end
   end
 end