Extended Web IDE API to get MRs for a certain branch in a project

 New `Api.projectMergeRequests` allows:
 - to query for all MRs on a project without specifying `mergeRequestId`
 - to filter the returned MRs using parameters from
 https://bit.ly/2H7We4V

 The new API request is used for fetching information about MRs
 associated with a particular branch in Web IDE to have IdeSidebar
 behave consistently in both scenarios:
 - getting to a branch from and MR (where we already have info about
 relevant MR), or
 - getting to a branch somehow differently directly

For cases where there are several merge requests that the current branch
is associated with, mark the most recent one as 'current'

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/49663

2 files changed, 94 insertions, 0 deletions

diff --git a/spec/javascripts/ide/stores/actions/merge_request_spec.js b/spec/javascripts/ide/stores/actions/merge_request_spec.js
index 9bfc7c397b8..a5839630657 100644
--- a/spec/javascripts/ide/stores/actions/merge_request_spec.js
+++ b/spec/javascripts/ide/stores/actions/merge_request_spec.js
@@ -2,6 +2,7 @@ import MockAdapter from 'axios-mock-adapter';
 import axios from '~/lib/utils/axios_utils';
 import store from '~/ide/stores';
 import actions, {
+  getMergeRequestsForBranch,
   getMergeRequestData,
   getMergeRequestChanges,
   getMergeRequestVersions,
@@ -27,6 +28,98 @@ describe('IDE store merge request actions', () => {
     resetStore(store);
   });
 
+  describe('getMergeRequestsForBranch', () => {
+    describe('success', () => {
+      const mrData = { iid: 2, source_branch: 'bar' };
+      const mockData = [mrData];
+
+      describe('base case', () => {
+        beforeEach(() => {
+          spyOn(service, 'getProjectMergeRequests').and.callThrough();
+          mock.onGet(/api\/(.*)\/projects\/abcproject\/merge_requests/).reply(200, mockData);
+        });
+
+        it('calls getProjectMergeRequests service method', done => {
+          store
+            .dispatch('getMergeRequestsForBranch', { projectId: 'abcproject', branchId: 'bar' })
+            .then(() => {
+              expect(service.getProjectMergeRequests).toHaveBeenCalledWith('abcproject', {
+                source_branch: 'bar',
+                order_by: 'created_at',
+                per_page: 1,
+              });
+
+              done();
+            })
+            .catch(done.fail);
+        });
+
+        it('sets the "Merge Request" Object', done => {
+          store
+            .dispatch('getMergeRequestsForBranch', { projectId: 'abcproject', branchId: 'bar' })
+            .then(() => {
+              expect(Object.keys(store.state.projects.abcproject.mergeRequests).length).toEqual(1);
+              expect(Object.keys(store.state.projects.abcproject.mergeRequests)[0]).toEqual('2');
+              expect(store.state.projects.abcproject.mergeRequests[2]).toEqual(
+                jasmine.objectContaining(mrData),
+              );
+              done();
+            })
+            .catch(done.fail);
+        });
+
+        it('sets "Current Merge Request" object to the most recent MR', done => {
+          store
+            .dispatch('getMergeRequestsForBranch', { projectId: 'abcproject', branchId: 'bar' })
+            .then(() => {
+              expect(store.state.currentMergeRequestId).toEqual('2');
+              done();
+            })
+            .catch(done.fail);
+        });
+      });
+
+      describe('no merge requests for branch available case', () => {
+        beforeEach(() => {
+          spyOn(service, 'getProjectMergeRequests').and.callThrough();
+          mock.onGet(/api\/(.*)\/projects\/abcproject\/merge_requests/).reply(200, []);
+        });
+
+        it('does not fail if there are no merge requests for current branch', done => {
+          store
+            .dispatch('getMergeRequestsForBranch', { projectId: 'abcproject', branchId: 'foo' })
+            .then(() => {
+              expect(Object.keys(store.state.projects.abcproject.mergeRequests).length).toEqual(0);
+              expect(store.state.currentMergeRequestId).toEqual('');
+              done();
+            })
+            .catch(done.fail);
+        });
+      });
+    });
+
+    describe('error', () => {
+      beforeEach(() => {
+        mock.onGet(/api\/(.*)\/projects\/abcproject\/merge_requests/).networkError();
+      });
+
+      it('flashes message, if error', done => {
+        const flashSpy = spyOnDependency(actions, 'flash');
+
+        getMergeRequestsForBranch({ commit() {} }, { projectId: 'abcproject', branchId: 'bar' })
+          .then(() => {
+            fail('Expected getMergeRequestsForBranch to throw an error');
+          })
+          .catch(() => {
+            expect(flashSpy).toHaveBeenCalled();
+            expect(flashSpy.calls.argsFor(0)[0]).toEqual('Error fetching merge requests for bar');
+          })
+          .then(done)
+          .catch(done.fail);
+      });
+    });
+  });
+
   describe('getMergeRequestData', () => {
     describe('success', () => {
       beforeEach(() => {
diff --git a/spec/javascripts/ide/stores/actions/project_spec.js b/spec/javascripts/ide/stores/actions/project_spec.js
index 7d8c9edd965..7b0963713fb 100644
--- a/spec/javascripts/ide/stores/actions/project_spec.js
+++ b/spec/javascripts/ide/stores/actions/project_spec.js
@@ -249,6 +249,7 @@ describe('IDE store project actions', () => {
             ['setCurrentBranchId', branch.branchId],
             ['getBranchData', branch],
             ['getFiles', branch],
+            ['getMergeRequestsForBranch', branch],
           ]);
         })
         .then(done)