specs: add spec for switch_lang action

Author: markets

spec/controllers/application_controller_spec.rb

@@ -0,0 +1,25 @@
+require 'spec_helper'
+
+RSpec.describe ApplicationController do
+  describe '#switch_lang' do
+    let(:original_locale) { I18n.locale }
+
+    before do
+      request.env["HTTP_REFERER"] = root_path
+    end
+
+    after do
+      I18n.locale = original_locale
+    end
+
+    it 'switches locale to passed language via params' do
+      new_locale = (I18n.available_locales - [original_locale]).sample
+
+      expect do
+        get :switch_lang, locale: new_locale
+      end.to change(I18n, :locale).from(original_locale).to(new_locale)
+
+      expect(response).to redirect_to(root_path)
+    end
+  end
+end