Add QA test to download merge request patch/diffs

app/assets/javascripts/vue_merge_request_widget/components/mr_widget_header.vue

@@ -135,7 +135,7 @@ export default {
         <span class="dropdown">
           <button
             type="button"
-            class="btn dropdown-toggle"
+            class="btn dropdown-toggle qa-dropdown-toggle"
             data-toggle="dropdown"
             aria-label="Download as"
             aria-haspopup="true"
@@ -145,12 +145,20 @@ export default {
           </button>
           <ul class="dropdown-menu dropdown-menu-right">
             <li>
-              <a :href="mr.emailPatchesPath" class="js-download-email-patches" download>
+              <a
+                :href="mr.emailPatchesPath"
+                class="js-download-email-patches qa-download-email-patches"
+                download
+              >
                 {{ s__('mrWidget|Email patches') }}
               </a>
             </li>
             <li>
-              <a :href="mr.plainDiffPath" class="js-download-plain-diff" download>
+              <a
+                :href="mr.plainDiffPath"
+                class="js-download-plain-diff qa-download-plain-diff"
+                download
+              >
                 {{ s__('mrWidget|Plain diff') }}
               </a>
             </li>

qa/qa/page/base.rb

@@ -157,6 +157,10 @@ module QA
         find('body').click
       end
 
+      def visit_link_in_element(name)
+        visit find_element(name)['href']
+      end
+
       def self.path
         raise NotImplementedError
       end

qa/qa/page/merge_request/show.rb

@@ -27,6 +27,12 @@ module QA
           element :squash_checkbox
         end
 
+        view 'app/assets/javascripts/vue_merge_request_widget/components/mr_widget_header.vue' do
+          element :dropdown_toggle
+          element :download_email_patches
+          element :download_plain_diff
+        end
+
         view 'app/views/projects/merge_requests/show.html.haml' do
           element :notes_tab
           element :diffs_tab
@@ -159,6 +165,16 @@ module QA
         def edit!
           click_element :edit_button
         end
+
+        def view_email_patches
+          click_element :dropdown_toggle
+          visit_link_in_element(:download_email_patches)
+        end
+
+        def view_plain_diff
+          click_element :dropdown_toggle
+          visit_link_in_element(:download_plain_diff)
+        end
       end
     end
   end

qa/qa/specs/features/browser_ui/3_create/merge_request/view_merge_request_diff_patch_spec.rb

+# frozen_string_literal: true
+
+module QA
+  context 'Create' do
+    describe 'Download merge request patch and diff' do
+      before(:context) do
+        Runtime::Browser.visit(:gitlab, Page::Main::Login)
+        Page::Main::Login.perform(&:sign_in_using_credentials)
+
+        @merge_request = Resource::MergeRequest.fabricate! do |merge_request|
+          merge_request.title = 'This is a merge request'
+          merge_request.description = 'For downloading patches and diffs'
+        end
+      end
+
+      it 'user views merge request email patches' do
+        @merge_request.visit!
+        Page::MergeRequest::Show.perform(&:view_email_patches)
+
+        expect(page.text).to start_with('From')
+        expect(page).to have_content('Subject: [PATCH] This is a test commit')
+        expect(page).to have_content('diff --git a/added_file.txt b/added_file.txt')
+      end
+
+      it 'user views merge request plain diff' do
+        @merge_request.visit!
+        Page::MergeRequest::Show.perform(&:view_plain_diff)
+
+        expect(page.text).to start_with('diff --git a/added_file.txt b/added_file.txt')
+        expect(page).to have_content('+File Added')
+      end
+    end
+  end
+end