Merge branch '65940-run-pipeline' into 'master'

Resolve "Run pipeline button for "Pipelines for merge requests""

Closes #65940

See merge request gitlab-org/gitlab-ce!31722

app/assets/javascripts/api.js

@@ -36,6 +36,7 @@ const Api = {
   branchSinglePath: '/api/:version/projects/:id/repository/branches/:branch',
   createBranchPath: '/api/:version/projects/:id/repository/branches',
   releasesPath: '/api/:version/projects/:id/releases',
+  mergeRequestsPipeline: '/api/:version/projects/:id/merge_requests/:merge_request_iid/pipelines',
   adminStatisticsPath: 'api/:version/application/statistics',
 
   group(groupId, callback) {
@@ -371,6 +372,14 @@ const Api = {
     });
   },
 
+  postMergeRequestPipeline(id, { mergeRequestId }) {
+    const url = Api.buildUrl(this.mergeRequestsPipeline)
+      .replace(':id', encodeURIComponent(id))
+      .replace(':merge_request_iid', mergeRequestId);
+
+    return axios.post(url);
+  },
+
   releases(id) {
     const url = Api.buildUrl(this.releasesPath).replace(':id', encodeURIComponent(id));
 

app/assets/javascripts/commit/pipelines/pipelines_table.vue

 <script>
-import PipelinesService from '../../pipelines/services/pipelines_service';
-import PipelineStore from '../../pipelines/stores/pipelines_store';
-import pipelinesMixin from '../../pipelines/mixins/pipelines';
-import TablePagination from '../../vue_shared/components/pagination/table_pagination.vue';
-import { getParameterByName } from '../../lib/utils/common_utils';
-import CIPaginationMixin from '../../vue_shared/mixins/ci_pagination_api_mixin';
+import { GlButton, GlLoadingIcon } from '@gitlab/ui';
+import PipelinesService from '~/pipelines/services/pipelines_service';
+import PipelineStore from '~/pipelines/stores/pipelines_store';
+import pipelinesMixin from '~/pipelines/mixins/pipelines';
+import eventHub from '~/pipelines/event_hub';
+import TablePagination from '~/vue_shared/components/pagination/table_pagination.vue';
+import { getParameterByName } from '~/lib/utils/common_utils';
+import CIPaginationMixin from '~/vue_shared/mixins/ci_pagination_api_mixin';
+import bp from '~/breakpoints';
 
 export default {
   components: {
     TablePagination,
+    GlButton,
+    GlLoadingIcon,
   },
   mixins: [pipelinesMixin, CIPaginationMixin],
   props: {
@@ -33,6 +38,21 @@ export default {
       required: false,
       default: 'child',
     },
+    canRunPipeline: {
+      type: Boolean,
+      required: false,
+      default: false,
+    },
+    projectId: {
+      type: String,
+      required: false,
+      default: '',
+    },
+    mergeRequestId: {
+      type: Number,
+      required: false,
+      default: 0,
+    },
   },
 
   data() {
@@ -53,6 +73,41 @@ export default {
     shouldRenderErrorState() {
       return this.hasError && !this.isLoading;
     },
+    /**
+     * The Run Pipeline button can only be rendered when:
+     * - In MR view -  we use `canRunPipeline` for that purpose
+     * - If the latest pipeline has the `detached_merge_request_pipeline` flag
+     *
+     * @returns {Boolean}
+     */
+    canRenderPipelineButton() {
+      return this.canRunPipeline && this.latestPipelineDetachedFlag;
+    },
+    /**
+     * Checks if either `detached_merge_request_pipeline` or
+     * `merge_request_pipeline` are tru in the first
+     * object in the pipelines array.
+     *
+     * @returns {Boolean}
+     */
+    latestPipelineDetachedFlag() {
+      const latest = this.state.pipelines[0];
+      return (
+        latest &&
+        latest.flags &&
+        (latest.flags.detached_merge_request_pipeline || latest.flags.merge_request_pipeline)
+      );
+    },
+    /**
+     * When we are on Desktop and the button is visible
+     * we need to add a negative margin to the table
+     * to make it inline with the button
+     *
+     * @returns {Boolean}
+     */
+    shouldAddNegativeMargin() {
+      return this.canRenderPipelineButton && bp.isDesktop();
+    },
   },
   created() {
     this.service = new PipelinesService(this.endpoint);
@@ -77,6 +132,22 @@ export default {
         this.$el.parentElement.dispatchEvent(updatePipelinesEvent);
       }
     },
+    /**
+     * When the user clicks on the Run Pipeline button
+     * we need to make a post request and
+     * to update the table content once the request is finished.
+     *
+     * We are emitting an event through the eventHub using the old pattern
+     * to make use of the code in mixins/pipelines.js that handles all the
+     * table events
+     *
+     */
+    onClickRunPipeline() {
+      eventHub.$emit('runMergeRequestPipeline', {
+        projectId: this.projectId,
+        mergeRequestId: this.mergeRequestId,
+      });
+    },
   },
 };
 </script>
@@ -99,11 +170,25 @@ export default {
     />
 
     <div v-else-if="shouldRenderTable" class="table-holder">
+      <div v-if="canRenderPipelineButton" class="nav justify-content-end">
+        <gl-button
+          v-if="canRenderPipelineButton"
+          variant="success"
+          class="js-run-mr-pipeline prepend-top-10 btn-wide-on-xs"
+          :disabled="state.isRunningMergeRequestPipeline"
+          @click="onClickRunPipeline"
+        >
+          <gl-loading-icon v-if="state.isRunningMergeRequestPipeline" inline />
+          {{ s__('Pipelines|Run Pipeline') }}
+        </gl-button>
+      </div>
+
       <pipelines-table-component
         :pipelines="state.pipelines"
         :update-graph-dropdown="updateGraphDropdown"
         :auto-devops-help-path="autoDevopsHelpPath"
         :view-type="viewType"
+        :class="{ 'negative-margin-top': shouldAddNegativeMargin }"
       />
     </div>
 

app/assets/javascripts/merge_request_tabs.js

@@ -333,7 +333,8 @@ export default class MergeRequestTabs {
 
   mountPipelinesView() {
     const pipelineTableViewEl = document.querySelector('#commit-pipeline-table-view');
-    const { CommitPipelinesTable } = gl;
+    const { CommitPipelinesTable, mrWidgetData } = gl;
+
     this.commitPipelinesTable = new CommitPipelinesTable({
       propsData: {
         endpoint: pipelineTableViewEl.dataset.endpoint,
@@ -341,6 +342,9 @@ export default class MergeRequestTabs {
         emptyStateSvgPath: pipelineTableViewEl.dataset.emptyStateSvgPath,
         errorStateSvgPath: pipelineTableViewEl.dataset.errorStateSvgPath,
         autoDevopsHelpPath: pipelineTableViewEl.dataset.helpAutoDevopsPath,
+        canRunPipeline: true,
+        projectId: pipelineTableViewEl.dataset.projectId,
+        mergeRequestId: mrWidgetData ? mrWidgetData.iid : null,
       },
     }).$mount();
 

app/assets/javascripts/pipelines/mixins/pipelines.js

 import Visibility from 'visibilityjs';
 import { GlLoadingIcon } from '@gitlab/ui';
 import { __ } from '../../locale';
-import Flash from '../../flash';
+import createFlash from '../../flash';
 import Poll from '../../lib/utils/poll';
 import EmptyState from '../components/empty_state.vue';
 import SvgBlankState from '../components/blank_state.vue';
@@ -62,6 +62,7 @@ export default {
     eventHub.$on('clickedDropdown', this.updateTable);
     eventHub.$on('updateTable', this.updateTable);
     eventHub.$on('refreshPipelinesTable', this.fetchPipelines);
+    eventHub.$on('runMergeRequestPipeline', this.runMergeRequestPipeline);
   },
   beforeDestroy() {
     eventHub.$off('postAction', this.postAction);
@@ -69,6 +70,7 @@ export default {
     eventHub.$off('clickedDropdown', this.updateTable);
     eventHub.$off('updateTable', this.updateTable);
     eventHub.$off('refreshPipelinesTable', this.fetchPipelines);
+    eventHub.$off('runMergeRequestPipeline', this.runMergeRequestPipeline);
   },
   destroyed() {
     this.poll.stop();
@@ -110,7 +112,7 @@ export default {
       // Stop polling
       this.poll.stop();
       // Restarting the poll also makes an initial request
-      this.poll.restart();
+      return this.poll.restart();
     },
     fetchPipelines() {
       if (!this.isMakingRequest) {
@@ -156,7 +158,31 @@ export default {
       this.service
         .postAction(endpoint)
         .then(() => this.updateTable())
-        .catch(() => Flash(__('An error occurred while making the request.')));
+        .catch(() => createFlash(__('An error occurred while making the request.')));
+    },
+
+    /**
+     * When the user clicks on the run pipeline button
+     * we toggle the state of the button to be disabled
+     *
+     * Once the post request has finished, we fetch the
+     * pipelines again to show the most recent data
+     *
+     * Once the pipeline has been updated, we toggle back the
+     * loading state and re-enable the run pipeline button
+     */
+    runMergeRequestPipeline(options) {
+      this.store.toggleIsRunningPipeline(true);
+
+      this.service
+        .runMRPipeline(options)
+        .then(() => this.updateTable())
+        .catch(() => {
+          createFlash(
+            __('An error occurred while trying to run a new pipeline for this Merge Request.'),
+          );
+        })
+        .finally(() => this.store.toggleIsRunningPipeline(false));
     },
   },
 };

app/assets/javascripts/pipelines/services/pipelines_service.js

 import axios from '../../lib/utils/axios_utils';
+import Api from '~/api';
 
 export default class PipelinesService {
   /**
@@ -39,4 +40,9 @@ export default class PipelinesService {
   postAction(endpoint) {
     return axios.post(`${endpoint}.json`);
   }
+
+  // eslint-disable-next-line class-methods-use-this
+  runMRPipeline({ projectId, mergeRequestId }) {
+    return Api.postMergeRequestPipeline(projectId, { mergeRequestId });
+  }
 }

app/assets/javascripts/pipelines/stores/pipelines_store.js

@@ -7,6 +7,9 @@ export default class PipelinesStore {
     this.state.pipelines = [];
     this.state.count = {};
     this.state.pageInfo = {};
+
+    // Used in MR Pipelines tab
+    this.state.isRunningMergeRequestPipeline = false;
   }
 
   storePipelines(pipelines = []) {
@@ -29,4 +32,13 @@ export default class PipelinesStore {
 
     this.state.pageInfo = paginationInfo;
   }
+
+  /**
+   * Toggles the isRunningPipeline flag
+   *
+   * @param {Boolean} value
+   */
+  toggleIsRunningPipeline(value = false) {
+    this.state.isRunningMergeRequestPipeline = value;
+  }
 }

app/assets/stylesheets/framework/variables.scss

@@ -726,6 +726,7 @@ $pipeline-dropdown-line-height: 20px;
 $pipeline-dropdown-status-icon-size: 18px;
 $ci-action-dropdown-button-size: 24px;
 $ci-action-dropdown-svg-size: 12px;
+$pipelines-table-header-height: 40px;
 
 /*
 CI variable lists

app/assets/stylesheets/pages/pipelines.scss

@@ -26,6 +26,10 @@
 }
 
 .pipelines {
+  .negative-margin-top {
+    margin-top: -$pipelines-table-header-height;
+  }
+
   .stage {
     max-width: 90px;
     width: 90px;

app/views/projects/commit/_pipelines_list.haml

@@ -5,4 +5,5 @@
   "help-auto-devops-path" => help_page_path('topics/autodevops/index.md'),
   "empty-state-svg-path" => image_path('illustrations/pipelines_empty.svg'),
   "error-state-svg-path" => image_path('illustrations/pipelines_failed.svg'),
+  "project-id": @project.id,
 } }

changelogs/unreleased/65940-run-pipeline.yml

+---
+title: Run Pipeline button & API for MR Pipelines
+merge_request: 31722
+author:
+type: added

doc/api/merge_requests.md

@@ -821,6 +821,66 @@ Parameters:
 ]
 ```
 
+## Create MR Pipeline
+
+> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31722) in Gitlab 12.3.
+
+Create a new [pipeline for a merge request](../ci/merge_request_pipelines/index.md). A pipeline created via this endpoint will not run a regular branch/tag pipeline, it requires `.gitlab-ci.yml` to be configured with `only: [merge_requests]` to create jobs.
+
+The new pipeline can be:
+
+- A detached merge request pipeline.
+- A [pipeline for merged results](../ci/merge_request_pipelines/pipelines_for_merged_results/index.md)
+  if the [project setting is enabled](../ci/merge_request_pipelines/pipelines_for_merged_results/index.md#enabling-pipelines-for-merged-results).
+
+```
+POST /projects/:id/merge_requests/:merge_request_iid/pipelines
+```
+
+Parameters:
+
+- `id` (required) - The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding)
+- `merge_request_iid` (required) - The internal ID of the merge request
+
+```json
+{
+  "id": 2,
+  "sha": "b83d6e391c22777fca1ed3012fce84f633d7fed0",
+  "ref": "refs/merge-requests/1/head",
+  "status": "pending",
+  "web_url": "http://localhost/user1/project1/pipelines/2",
+  "before_sha": "0000000000000000000000000000000000000000",
+  "tag": false,
+  "yaml_errors": null,
+  "user": {
+    "id": 1,
+    "name": "John Doe1",
+    "username": "user1",
+    "state": "active",
+    "avatar_url": "https://www.gravatar.com/avatar/c922747a93b40d1ea88262bf1aebee62?s=80&d=identicon",
+    "web_url": "http://example.com"
+  },
+  "created_at": "2019-09-04T19:20:18.267Z",
+  "updated_at": "2019-09-04T19:20:18.459Z",
+  "started_at": null,
+  "finished_at": null,
+  "committed_at": null,
+  "duration": null,
+  "coverage": null,
+  "detailed_status": {
+    "icon": "status_pending",
+    "text": "pending",
+    "label": "pending",
+    "group": "pending",
+    "tooltip": "pending",
+    "has_details": false,
+    "details_path": "/user1/project1/pipelines/2",
+    "illustration": null,
+    "favicon": "/assets/ci_favicons/favicon_status_pending-5bdf338420e5221ca24353b6bff1c9367189588750632e9a871b7af09ff6a2ae.png"
+  }
+}
+```
+
 ## Create MR
 
 Creates a new merge request.

lib/api/merge_requests.rb

@@ -317,6 +317,26 @@ module API
         present paginate(pipelines), with: Entities::PipelineBasic
       end
 
+      desc 'Create a pipeline for merge request' do
+        success Entities::Pipeline
+      end
+      post ':id/merge_requests/:merge_request_iid/pipelines' do
+        authorize! :create_pipeline, user_project
+
+        pipeline = ::MergeRequests::CreatePipelineService
+          .new(user_project, current_user, allow_duplicate: true)
+          .execute(find_merge_request_with_access(params[:merge_request_iid]))
+
+        if pipeline.nil?
+          not_allowed!
+        elsif pipeline.persisted?
+          status :ok
+          present pipeline, with: Entities::Pipeline
+        else
+          render_validation_error!(pipeline)
+        end
+      end
+
       desc 'Update a merge request' do
         success Entities::MergeRequest
       end

locale/gitlab.pot

@@ -1146,6 +1146,9 @@ msgstr ""
 msgid "An error occurred while triggering the job."
 msgstr ""
 
+msgid "An error occurred while trying to run a new pipeline for this Merge Request."
+msgstr ""
+
 msgid "An error occurred while validating username"
 msgstr ""
 

spec/features/merge_request/user_sees_pipelines_spec.rb

@@ -45,6 +45,38 @@ describe 'Merge request > User sees pipelines', :js do
 
         expect(page.find('.ci-widget')).to have_text("Could not retrieve the pipeline status. For troubleshooting steps, read the documentation.")
       end
+
+      context 'with a detached merge request pipeline' do
+        let(:merge_request) { create(:merge_request, :with_detached_merge_request_pipeline) }
+
+        it 'displays the Run Pipeline button' do
+          visit project_merge_request_path(project, merge_request)
+
+          page.within('.merge-request-tabs') do
+            click_link('Pipelines')
+          end
+
+          wait_for_requests
+
+          expect(page.find('.js-run-mr-pipeline')).to have_text('Run Pipeline')
+        end
+      end
+
+      context 'with a merged results pipeline' do
+        let(:merge_request) { create(:merge_request, :with_merge_request_pipeline) }
+
+        it 'displays the Run Pipeline button' do
+          visit project_merge_request_path(project, merge_request)
+
+          page.within('.merge-request-tabs') do
+            click_link('Pipelines')
+          end
+
+          wait_for_requests
+
+          expect(page.find('.js-run-mr-pipeline')).to have_text('Run Pipeline')
+        end
+      end
     end
 
     context 'without pipelines' do

spec/javascripts/commit/pipelines/pipelines_spec.js

 import Vue from 'vue';
 import MockAdapter from 'axios-mock-adapter';
 import axios from '~/lib/utils/axios_utils';
+import Api from '~/api';
 import pipelinesTable from '~/commit/pipelines/pipelines_table.vue';
 import mountComponent from 'spec/helpers/vue_mount_component_helper';
 
@@ -10,6 +11,13 @@ describe('Pipelines table in Commits and Merge requests', function() {
   let PipelinesTable;
   let mock;
   let vm;
+  const props = {
+    endpoint: 'endpoint.json',
+    helpPagePath: 'foo',
+    emptyStateSvgPath: 'foo',
+    errorStateSvgPath: 'foo',
+    autoDevopsHelpPath: 'foo',
+  };
 
   preloadFixtures(jsonFixtureName);
 
@@ -32,13 +40,7 @@ describe('Pipelines table in Commits and Merge requests', function() {
       beforeEach(function() {
         mock.onGet('endpoint.json').reply(200, []);
 
-        vm = mountComponent(PipelinesTable, {
-          endpoint: 'endpoint.json',
-          helpPagePath: 'foo',
-          emptyStateSvgPath: 'foo',
-          errorStateSvgPath: 'foo',
-          autoDevopsHelpPath: 'foo',
-        });
+        vm = mountComponent(PipelinesTable, props);
       });
 
       it('should render the empty state', function(done) {
@@ -54,13 +56,7 @@ describe('Pipelines table in Commits and Merge requests', function() {
     describe('with pipelines', () => {
       beforeEach(() => {
         mock.onGet('endpoint.json').reply(200, [pipeline]);
-        vm = mountComponent(PipelinesTable, {
-          endpoint: 'endpoint.json',
-          helpPagePath: 'foo',
-          emptyStateSvgPath: 'foo',
-          errorStateSvgPath: 'foo',
-          autoDevopsHelpPath: 'foo',
-        });
+        vm = mountComponent(PipelinesTable, props);
       });
 
       it('should render a table with the received pipelines', done => {
@@ -111,30 +107,145 @@ describe('Pipelines table in Commits and Merge requests', function() {
           done();
         });
 
-        vm = mountComponent(PipelinesTable, {
-          endpoint: 'endpoint.json',
-          helpPagePath: 'foo',
-          emptyStateSvgPath: 'foo',
-          errorStateSvgPath: 'foo',
-          autoDevopsHelpPath: 'foo',
-        });
+        vm = mountComponent(PipelinesTable, props);
 
         element.appendChild(vm.$el);
       });
     });
   });
 
+  describe('run pipeline button', () => {
+    let pipelineCopy;
+
+    beforeEach(() => {
+      pipelineCopy = Object.assign({}, pipeline);
+    });
+
+    describe('when latest pipeline has detached flag and canRunPipeline is true', () => {
+      it('renders the run pipeline button', done => {
+        pipelineCopy.flags.detached_merge_request_pipeline = true;
+        pipelineCopy.flags.merge_request_pipeline = true;
+
+        mock.onGet('endpoint.json').reply(200, [pipelineCopy]);
+
+        vm = mountComponent(
+          PipelinesTable,
+          Object.assign({}, props, {
+            canRunPipeline: true,
+          }),
+        );
+
+        setTimeout(() => {
+          expect(vm.$el.querySelector('.js-run-mr-pipeline')).not.toBeNull();
+          done();
+        });
+      });
+    });
+
+    describe('when latest pipeline has detached flag and canRunPipeline is false', () => {
+      it('does not render the run pipeline button', done => {
+        pipelineCopy.flags.detached_merge_request_pipeline = true;
+        pipelineCopy.flags.merge_request_pipeline = true;
+
+        mock.onGet('endpoint.json').reply(200, [pipelineCopy]);
+
+        vm = mountComponent(
+          PipelinesTable,
+          Object.assign({}, props, {
+            canRunPipeline: false,
+          }),
+        );
+
+        setTimeout(() => {
+          expect(vm.$el.querySelector('.js-run-mr-pipeline')).toBeNull();
+          done();
+        });
+      });
+    });
+
+    describe('when latest pipeline does not have detached flag and canRunPipeline is true', () => {
+      it('does not render the run pipeline button', done => {
+        pipelineCopy.flags.detached_merge_request_pipeline = false;
+        pipelineCopy.flags.merge_request_pipeline = false;
+
+        mock.onGet('endpoint.json').reply(200, [pipelineCopy]);
+
+        vm = mountComponent(
+          PipelinesTable,
+          Object.assign({}, props, {
+            canRunPipeline: true,
+          }),
+        );
+
+        setTimeout(() => {
+          expect(vm.$el.querySelector('.js-run-mr-pipeline')).toBeNull();
+          done();
+        });
+      });
+    });
+
+    describe('when latest pipeline does not have detached flag and merge_request_pipeline is true', () => {
+      it('does not render the run pipeline button', done => {
+        pipelineCopy.flags.detached_merge_request_pipeline = false;
+        pipelineCopy.flags.merge_request_pipeline = true;
+
+        mock.onGet('endpoint.json').reply(200, [pipelineCopy]);
+
+        vm = mountComponent(
+          PipelinesTable,
+          Object.assign({}, props, {
+            canRunPipeline: false,
+          }),
+        );
+
+        setTimeout(() => {
+          expect(vm.$el.querySelector('.js-run-mr-pipeline')).toBeNull();
+          done();
+        });
+      });
+    });
+
+    describe('on click', () => {
+      beforeEach(() => {
+        pipelineCopy.flags.detached_merge_request_pipeline = true;
+
+        mock.onGet('endpoint.json').reply(200, [pipelineCopy]);
+
+        vm = mountComponent(
+          PipelinesTable,
+          Object.assign({}, props, {
+            canRunPipeline: true,
+            projectId: '5',
+            mergeRequestId: 3,
+          }),
+        );
+      });
+
+      it('updates the loading state', done => {
+        spyOn(Api, 'postMergeRequestPipeline').and.returnValue(Promise.resolve());
+
+        setTimeout(() => {
+          vm.$el.querySelector('.js-run-mr-pipeline').click();
+
+          vm.$nextTick(() => {
+            expect(vm.state.isRunningMergeRequestPipeline).toBe(true);
+
+            setTimeout(() => {
+              expect(vm.state.isRunningMergeRequestPipeline).toBe(false);
+
+              done();
+            });
+          });
+        });
+      });
+    });
+  });
+
   describe('unsuccessfull request', () => {
     beforeEach(() => {
       mock.onGet('endpoint.json').reply(500, []);
 
-      vm = mountComponent(PipelinesTable, {
-        endpoint: 'endpoint.json',
-        helpPagePath: 'foo',
-        emptyStateSvgPath: 'foo',
-        errorStateSvgPath: 'foo',
-        autoDevopsHelpPath: 'foo',
-      });
+      vm = mountComponent(PipelinesTable, props);
     });
 
     it('should render error state', function(done) {

spec/models/ci/pipeline_spec.rb

@@ -579,14 +579,22 @@ describe Ci::Pipeline, :mailer do
   end
 
   describe 'Validations for merge request pipelines' do
-    let(:pipeline) { build(:ci_pipeline, source: source, merge_request: merge_request) }
+    let(:pipeline) do
+      build(:ci_pipeline, source: source, merge_request: merge_request)
+    end
+
+    let(:merge_request) do
+      create(:merge_request,
+        source_project: project,
+        source_branch:  'feature',
+        target_project: project,
+        target_branch:  'master')
+    end
 
     context 'when source is merge request' do
       let(:source) { :merge_request_event }
 
       context 'when merge request is specified' do
-        let(:merge_request) { create(:merge_request, source_project: project, source_branch: 'feature', target_project: project, target_branch: 'master') }
-
         it { expect(pipeline).to be_valid }
       end
 
@@ -601,8 +609,6 @@ describe Ci::Pipeline, :mailer do
       let(:source) { :web }
 
       context 'when merge request is specified' do
-        let(:merge_request) { create(:merge_request, source_project: project, source_branch: 'feature', target_project: project, target_branch: 'master') }
-
         it { expect(pipeline).not_to be_valid }
       end
 

spec/requests/api/merge_requests_spec.rb

@@ -1033,6 +1033,70 @@ describe API::MergeRequests do
     end
   end
 
+  describe 'POST /projects/:id/merge_requests/:merge_request_iid/pipelines' do
+    before do
+      allow_any_instance_of(Ci::Pipeline)
+        .to receive(:ci_yaml_file)
+        .and_return(YAML.dump({
+          rspec: {
+            script: 'ls',
+            only: ['merge_requests']
+          }
+        }))
+    end
+
+    let(:project) do
+      create(:project, :private, :repository,
+        creator: user,
+        namespace: user.namespace,
+        only_allow_merge_if_pipeline_succeeds: false)
+    end
+
+    let(:merge_request) do
+      create(:merge_request, :with_detached_merge_request_pipeline,
+        milestone: milestone1,
+        author: user,
+        assignees: [user],
+        source_project: project,
+        target_project: project,
+        title: 'Test',
+        created_at: base_time)
+    end
+
+    let(:merge_request_iid)  { merge_request.iid }
+    let(:authenticated_user) { user }
+
+    let(:request) do
+      post api("/projects/#{project.id}/merge_requests/#{merge_request_iid}/pipelines", authenticated_user)
+    end
+
+    context 'when authorized' do
+      it 'creates and returns the new Pipeline' do
+        expect { request }.to change(Ci::Pipeline, :count).by(1)
+        expect(response).to have_gitlab_http_status(200)
+        expect(json_response).to be_a Hash
+      end
+    end
+
+    context 'when unauthorized' do
+      let(:authenticated_user) { create(:user) }
+
+      it 'responds with a blank 404' do
+        expect { request }.not_to change(Ci::Pipeline, :count)
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+
+    context 'when the merge request does not exist' do
+      let(:merge_request_iid) { 777 }
+
+      it 'responds with a blank 404' do
+        expect { request }.not_to change(Ci::Pipeline, :count)
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+  end
+
   describe 'POST /projects/:id/merge_requests' do
     context 'support for deprecated assignee_id' do
       let(:params) do

spec/services/merge_requests/create_pipeline_service_spec.rb

@@ -38,6 +38,10 @@ describe MergeRequests::CreatePipelineService do
       expect(subject).to be_detached_merge_request_pipeline
     end
 
+    it 'defaults to merge_request_event' do
+      expect(subject.source).to eq('merge_request_event')
+    end
+
     context 'when service is called multiple times' do
       it 'creates a pipeline once' do
         expect do