Make MR pipeline widget text more descriptive (EE)

This change updates the text of the pipeline widget that appears on the
merge request page. The text has been made more consistent between
different types of pipelines; this makes the front-end implementation
simpler and more maintainable.  In addition, the type of pipeline is
(i.e. regular pipeline, merge request pipeline, detached pipeline)
included in the text, making this type more obvious to the end user.

Some information has been removed from the widget as part of this
change; however, any information that was removed already appears
elsewhere on the merge request page.

ee/spec/factories/merge_requests.rb

@@ -24,6 +24,15 @@ FactoryBot.modify do
       end
     end
 
+    trait :with_merge_train_pipeline do
+      with_merge_request_pipeline
+
+      after(:create) do |merge_request, evaluator|
+        merge_request.pipelines_for_merge_request.last
+          .update(ref: merge_request.train_ref_path)
+      end
+    end
+
     trait :add_to_merge_train_when_pipeline_succeeds do
       auto_merge_enabled true
       auto_merge_strategy AutoMergeService::STRATEGY_ADD_TO_MERGE_TRAIN_WHEN_PIPELINE_SUCCEEDS

ee/spec/features/merge_request/user_sees_merge_widget_spec.rb

@@ -47,6 +47,24 @@ describe 'Merge request > User sees merge widget', :js do
       end
     end
 
+    context 'when the head pipeline is merge train pipeline' do
+      let(:traits) { [:with_merge_train_pipeline] }
+      let(:options) { { merge_sha: project.commit.sha } }
+      let(:pipeline) { merge_request.all_pipelines.first }
+
+      before do
+        merge_request.update_head_pipeline
+      end
+
+      it 'shows head pipeline information' do
+        visit project_merge_request_path(project, merge_request)
+
+        within '.ci-widget-content' do
+          expect(page).to have_content("Merge train pipeline ##{pipeline.id} pending for #{pipeline.short_sha}")
+        end
+      end
+    end
+
     context 'when merge request is submitted from a forked project' do
       let(:source_project) { fork_project(project, user, repository: true) }
       let(:traits) { [:with_detached_merge_request_pipeline] }

ee/spec/javascripts/vue_mr_widget/mr_widget_pipeline_spec.js

@@ -3,6 +3,7 @@ import pipelineComponent from '~/vue_merge_request_widget/components/mr_widget_p
 import mountComponent from 'spec/helpers/vue_mount_component_helper';
 import mockData from 'ee_spec/vue_mr_widget/mock_data';
 import mockLinkedPipelines from 'ee_spec/pipelines/graph/linked_pipelines_mock_data';
+import { trimText } from 'spec/helpers/text_helper';
 
 describe('MRWidgetPipeline', () => {
   let vm;
@@ -55,4 +56,53 @@ describe('MRWidgetPipeline', () => {
       });
     });
   });
+
+  describe('for each type of pipeline', () => {
+    let pipeline;
+
+    beforeEach(() => {
+      ({ pipeline } = JSON.parse(JSON.stringify(mockData)));
+
+      pipeline.ref.tag = false;
+      pipeline.ref.branch = false;
+    });
+
+    const factory = () => {
+      vm = mountComponent(Component, {
+        pipeline,
+        hasCi: true,
+        ciStatus: 'success',
+        troubleshootingDocsPath: 'help',
+        sourceBranchLink: mockData.source_branch_link,
+      });
+    };
+
+    describe('for a merge train pipeline', () => {
+      it('renders a pipeline widget that reads "Merge train pipeline <ID> <status> for <SHA>"', () => {
+        pipeline.details.name = 'Merge train pipeline';
+        pipeline.merge_request_event_type = 'merge_train';
+
+        factory();
+
+        const expected = `Merge train pipeline #${pipeline.id} ${pipeline.details.status.label} for ${pipeline.commit.short_id}`;
+        const actual = trimText(vm.$el.querySelector('.js-pipeline-info-container').innerText);
+
+        expect(actual).toBe(expected);
+      });
+    });
+
+    describe('for a merged result pipeline', () => {
+      it('renders a pipeline widget that reads "Merged result pipeline <ID> <status> for <SHA>"', () => {
+        pipeline.details.name = 'Merged result pipeline';
+        pipeline.merge_request_event_type = 'merged_result';
+
+        factory();
+
+        const expected = `Merged result pipeline #${pipeline.id} ${pipeline.details.status.label} for ${pipeline.commit.short_id}`;
+        const actual = trimText(vm.$el.querySelector('.js-pipeline-info-container').innerText);
+
+        expect(actual).toBe(expected);
+      });
+    });
+  });
 });

locale/gitlab.pot

@@ -4226,9 +4226,6 @@ msgstr ""
 msgid "Could not remove the trigger."
 msgstr ""
 
-msgid "Could not retrieve the pipeline status. For troubleshooting steps, read the %{linkStart}documentation.%{linkEnd}"
-msgstr ""
-
 msgid "Could not revoke impersonation token %{token_name}."
 msgstr ""
 
@@ -11017,6 +11014,9 @@ msgstr ""
 msgid "Pipeline|Commit"
 msgstr ""
 
+msgid "Pipeline|Could not retrieve the pipeline status. For troubleshooting steps, read the %{linkStart}documentation.%{linkEnd}"
+msgstr ""
+
 msgid "Pipeline|Coverage"
 msgstr ""
 
@@ -11083,18 +11083,12 @@ msgstr ""
 msgid "Pipeline|for"
 msgstr ""
 
-msgid "Pipeline|into"
-msgstr ""
-
 msgid "Pipeline|on"
 msgstr ""
 
 msgid "Pipeline|success"
 msgstr ""
 
-msgid "Pipeline|with"
-msgstr ""
-
 msgid "Pipeline|with stage"
 msgstr ""