Add more tests to ee-only app settings

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/spec/features/admin/admin_settings_spec.rb

+require 'spec_helper'
+
+feature 'Admin updates EE-only settings' do
+  include StubENV
+
+  before do
+    stub_env('IN_MEMORY_APPLICATION_SETTINGS', 'false')
+    sign_in(create(:admin))
+    allow(License).to receive(:feature_available?).and_return(true)
+    visit admin_application_settings_path
+  end
+
+  scenario 'Modify GitLab Geo settings' do
+    page.within('.as-geo') do
+      fill_in 'Connection timeout', with: 15
+      click_button 'Save changes'
+    end
+
+    expect(Gitlab::CurrentSettings.geo_status_timeout).to eq(15)
+    expect(page).to have_content "Application settings saved successfully"
+  end
+
+  scenario 'Enable external authentication' do
+    page.within('.as-external-auth') do
+      check 'Enable classification control using an external service'
+      fill_in 'Default classification label', with: 'default'
+      click_button 'Save changes'
+    end
+
+    expect(page).to have_content "Application settings saved successfully"
+  end
+
+  scenario 'Enable elastic search indexing' do
+    page.within('.as-elasticsearch') do
+      check 'Elasticsearch indexing'
+      click_button 'Save changes'
+    end
+
+    expect(Gitlab::CurrentSettings.elasticsearch_indexing).to be_truthy
+    expect(page).to have_content "Application settings saved successfully"
+  end
+
+  scenario 'Enable Slack application' do
+    allow(Gitlab).to receive(:com?).and_return(true)
+    visit admin_application_settings_path
+
+    page.within('.as-slack') do
+      check 'Enable Slack application'
+      click_button 'Save changes'
+    end
+
+    expect(page).to have_content "Application settings saved successfully"
+  end
+end