Add merge requests list endpoint for groups

5 files changed, 452 insertions, 230 deletions

diff --git a/changelogs/unreleased/issue_45082.yml b/changelogs/unreleased/issue_45082.yml
new file mode 100644
index 00000000000..b916a36c17b
--- /dev/null
+++ b/changelogs/unreleased/issue_45082.yml
@@ -0,0 +1,5 @@
+---
+title: Add merge requests list endpoint for groups
+merge_request:
+author:
+type: other
diff --git a/doc/api/merge_requests.md b/doc/api/merge_requests.md
index 8849f490c4f..051d2a10bc6 100644
--- a/doc/api/merge_requests.md
+++ b/doc/api/merge_requests.md
@@ -240,6 +240,112 @@ Parameters:
 ]
 ```
 
+## List group merge requests
+
+Get all merge requests for this group and its subgroups.
+The `state` parameter can be used to get only merge requests with a given state (`opened`, `closed`, or `merged`) or all of them (`all`).
+The pagination parameters `page` and `per_page` can be used to restrict the list of merge requests.
+
+```
+GET /groups/:id/merge_requests
+GET /groups/:id/merge_requests?state=opened
+GET /groups/:id/merge_requests?state=all
+GET /groups/:id/merge_requests?milestone=release
+GET /groups/:id/merge_requests?labels=bug,reproduced
+GET /groups/:id/merge_requests?my_reaction_emoji=star
+```
+
+`group_id` represents the ID of the group which contains the project where the MR resides.
+
+Parameters:
+
+| Attribute           | Type           | Required | Description                                                                                                                    |
+| ------------------- | -------------- | -------- | ------------------------------------------------------------------------------------------------------------------------------ |
+| `id`                | integer        | yes      | The ID of a group                                                                                                           |
+| `state`             | string         | no       | Return all merge requests or just those that are `opened`, `closed`, or `merged`                                               |
+| `order_by`          | string         | no       | Return merge requests ordered by `created_at` or `updated_at` fields. Default is `created_at`                                        |
+| `sort`              | string         | no       | Return merge requests sorted in `asc` or `desc` order. Default is `desc`                                                             |
+| `milestone`         | string         | no       | Return merge requests for a specific milestone                                                                                 |
+| `view`              | string         | no       | If `simple`, returns the `iid`, URL, title, description, and basic state of merge request                                      |
+| `labels`            | string         | no       | Return merge requests matching a comma separated list of labels                                                                |
+| `created_after`     | datetime       | no       | Return merge requests created on or after the given time                                                                       |
+| `created_before`    | datetime       | no       | Return merge requests created on or before the given time                                                                      |
+| `updated_after`     | datetime       | no       | Return merge requests updated on or after the given time                                                                       |
+| `updated_before`    | datetime       | no       | Return merge requests updated on or before the given time                                                                      |
+| `scope`             | string         | no       | Return merge requests for the given scope: `created_by_me`, `assigned_to_me` or `all`.<br>                                     |
+| `author_id`         | integer        | no       | Returns merge requests created by the given user `id` _([Introduced][ce-13060] in GitLab 9.5)_                                 |
+| `assignee_id`       | integer        | no       | Returns merge requests assigned to the given user `id` _([Introduced][ce-13060] in GitLab 9.5)_                                |
+| `my_reaction_emoji` | string         | no       | Return merge requests reacted by the authenticated user by the given `emoji` _([Introduced][ce-14016] in GitLab 10.0)_         |
+| `source_branch`     | string   | no       | Return merge requests with the given source branch                                                                     |
+| `target_branch`     | string   | no       | Return merge requests with the given target branch                                                                     |
+| `search`            | string         | no       | Search merge requests against their `title` and `description`                                                                  |
+
+```json
+[
+  {
+    "id": 1,
+    "iid": 1,
+    "target_branch": "master",
+    "source_branch": "test1",
+    "project_id": 3,
+    "title": "test1",
+    "state": "opened",
+    "created_at": "2017-04-29T08:46:00Z",
+    "updated_at": "2017-04-29T08:46:00Z",
+    "upvotes": 0,
+    "downvotes": 0,
+    "author": {
+      "id": 1,
+      "username": "admin",
+      "email": "admin@example.com",
+      "name": "Administrator",
+      "state": "active",
+      "created_at": "2012-04-29T08:46:00Z"
+    },
+    "assignee": {
+      "id": 1,
+      "username": "admin",
+      "email": "admin@example.com",
+      "name": "Administrator",
+      "state": "active",
+      "created_at": "2012-04-29T08:46:00Z"
+    },
+    "source_project_id": 2,
+    "target_project_id": 3,
+    "labels": [ ],
+    "description": "fixed login page css paddings",
+    "work_in_progress": false,
+    "milestone": {
+      "id": 5,
+      "iid": 1,
+      "project_id": 3,
+      "title": "v2.0",
+      "description": "Assumenda aut placeat expedita exercitationem labore sunt enim earum.",
+      "state": "closed",
+      "created_at": "2015-02-02T19:49:26.013Z",
+      "updated_at": "2015-02-02T19:49:26.013Z",
+      "due_date": null
+    },
+    "merge_when_pipeline_succeeds": true,
+    "merge_status": "can_be_merged",
+    "sha": "8888888888888888888888888888888888888888",
+    "merge_commit_sha": null,
+    "user_notes_count": 1,
+    "changes_count": "1",
+    "should_remove_source_branch": true,
+    "force_remove_source_branch": false,
+    "web_url": "http://example.com/example/example/merge_requests/1",
+    "discussion_locked": false,
+    "time_stats": {
+      "time_estimate": 0,
+      "total_time_spent": 0,
+      "human_time_estimate": null,
+      "human_total_time_spent": null
+    }
+  }
+]
+```
+
 ## Get single MR
 
 Shows information about a single merge request.
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index 1ba9a09346f..b1e510d72de 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -59,6 +59,18 @@ module API
         end
       end
 
+      def serializer_options_for(merge_requests)
+        options = { with: Entities::MergeRequestBasic, current_user: current_user }
+
+        if params[:view] == 'simple'
+          options[:with] = Entities::MergeRequestSimple
+        else
+          options[:issuable_metadata] = issuable_meta_data(merge_requests, 'MergeRequest')
+        end
+
+        options
+      end
+
       params :merge_requests_params do
         optional :state, type: String, values: %w[opened closed merged all], default: 'all',
                          desc: 'Return opened, closed, merged, or all merge requests'
@@ -98,16 +110,26 @@ module API
         authenticate! unless params[:scope] == 'all'
         merge_requests = find_merge_requests
 
-        options = { with: Entities::MergeRequestBasic,
-                    current_user: current_user }
+        present merge_requests, serializer_options_for(merge_requests)
+      end
+    end
 
-        if params[:view] == 'simple'
-          options[:with] = Entities::MergeRequestSimple
-        else
-          options[:issuable_metadata] = issuable_meta_data(merge_requests, 'MergeRequest')
-        end
+    params do
+      requires :id, type: String, desc: 'The ID of a group'
+    end
+    resource :groups, requirements: API::PROJECT_ENDPOINT_REQUIREMENTS do
+      desc 'Get a list of group merge requests' do
+        success Entities::MergeRequestBasic
+      end
+      params do
+        use :merge_requests_params
+      end
+      get ":id/merge_requests" do
+        group = find_group!(params[:id])
 
-        present merge_requests, options
+        merge_requests = find_merge_requests(group_id: group.id, include_subgroups: true)
+
+        present merge_requests, serializer_options_for(merge_requests)
       end
     end
 
@@ -159,15 +181,8 @@ module API
 
         merge_requests = find_merge_requests(project_id: user_project.id)
 
-        options = { with: Entities::MergeRequestBasic,
-                    current_user: current_user,
-                    project: user_project }
-
-        if params[:view] == 'simple'
-          options[:with] = Entities::MergeRequestSimple
-        else
-          options[:issuable_metadata] = issuable_meta_data(merge_requests, 'MergeRequest')
-        end
+        options = serializer_options_for(merge_requests)
+        options[:project] = user_project
 
         present merge_requests, options
       end
diff --git a/spec/requests/api/merge_requests_spec.rb b/spec/requests/api/merge_requests_spec.rb
index 8b168816d6c..605761867bf 100644
--- a/spec/requests/api/merge_requests_spec.rb
+++ b/spec/requests/api/merge_requests_spec.rb
@@ -72,12 +72,6 @@ describe API::MergeRequests do
 
         expect(response).to have_gitlab_http_status(401)
       end
-
-      it "returns authentication error when scope is created_by_me" do
-        get api("/merge_requests"), scope: 'created_by_me'
-
-        expect(response).to have_gitlab_http_status(401)
-      end
     end
 
     context 'when authenticated' do
@@ -229,224 +223,46 @@ describe API::MergeRequests do
   end
 
   describe "GET /projects/:id/merge_requests" do
-    context "when unauthenticated" do
-      it 'returns merge requests for public projects' do
-        get api("/projects/#{project.id}/merge_requests")
-
-        expect_paginated_array_response
-      end
-
-      it "returns 404 for non public projects" do
-        project = create(:project, :private)
-        get api("/projects/#{project.id}/merge_requests")
-
-        expect(response).to have_gitlab_http_status(404)
-      end
-    end
-
-    context "when authenticated" do
-      it 'avoids N+1 queries' do
-        control = ActiveRecord::QueryRecorder.new do
-          get api("/projects/#{project.id}/merge_requests", user)
-        end
+    let(:endpoint_path) { "/projects/#{project.id}/merge_requests" }
 
-        create(:merge_request, state: 'closed', milestone: milestone1, author: user, assignee: user, source_project: project, target_project: project, title: "Test", created_at: base_time)
-
-        create(:merge_request, milestone: milestone1, author: user, assignee: user, source_project: project, target_project: project, title: "Test", created_at: base_time)
-
-        expect do
-          get api("/projects/#{project.id}/merge_requests", user)
-        end.not_to exceed_query_limit(control)
-      end
-
-      it "returns an array of all merge_requests" do
-        get api("/projects/#{project.id}/merge_requests", user)
-
-        expect_response_ordered_exactly(merge_request_merged, merge_request_closed, merge_request)
-        expect(json_response.last['title']).to eq(merge_request.title)
-        expect(json_response.last).to have_key('web_url')
-        expect(json_response.last['sha']).to eq(merge_request.diff_head_sha)
-        expect(json_response.last['merge_commit_sha']).to be_nil
-        expect(json_response.last['merge_commit_sha']).to eq(merge_request.merge_commit_sha)
-        expect(json_response.last['downvotes']).to eq(1)
-        expect(json_response.last['upvotes']).to eq(1)
-        expect(json_response.last['labels']).to eq([label2.title, label.title])
-        expect(json_response.first['title']).to eq(merge_request_merged.title)
-        expect(json_response.first['sha']).to eq(merge_request_merged.diff_head_sha)
-        expect(json_response.first['merge_commit_sha']).not_to be_nil
-        expect(json_response.first['merge_commit_sha']).to eq(merge_request_merged.merge_commit_sha)
-        expect(json_response.first['squash']).to eq(merge_request_merged.squash)
-      end
-
-      it "returns an array of all merge_requests using simple mode" do
-        get api("/projects/#{project.id}/merge_requests?view=simple", user)
-
-        expect_response_ordered_exactly(merge_request_merged, merge_request_closed, merge_request)
-        expect(json_response.last.keys).to match_array(%w(id iid title web_url created_at description project_id state updated_at))
-        expect(json_response.last['iid']).to eq(merge_request.iid)
-        expect(json_response.last['title']).to eq(merge_request.title)
-        expect(json_response.last).to have_key('web_url')
-        expect(json_response.first['iid']).to eq(merge_request_merged.iid)
-        expect(json_response.first['title']).to eq(merge_request_merged.title)
-        expect(json_response.first).to have_key('web_url')
-      end
-
-      it "returns an array of all merge_requests" do
-        get api("/projects/#{project.id}/merge_requests?state", user)
-
-        expect_response_ordered_exactly(merge_request_merged, merge_request_closed, merge_request)
-        expect(json_response.last['title']).to eq(merge_request.title)
-      end
-
-      it "returns an array of open merge_requests" do
-        get api("/projects/#{project.id}/merge_requests?state=opened", user)
-
-        expect_response_ordered_exactly(merge_request)
-        expect(json_response.last['title']).to eq(merge_request.title)
-      end
+    it_behaves_like 'merge requests list'
 
-      it "returns an array of closed merge_requests" do
-        get api("/projects/#{project.id}/merge_requests?state=closed", user)
-
-        expect_response_ordered_exactly(merge_request_closed)
-        expect(json_response.first['title']).to eq(merge_request_closed.title)
-      end
-
-      it "returns an array of merged merge_requests" do
-        get api("/projects/#{project.id}/merge_requests?state=merged", user)
-
-        expect_response_ordered_exactly(merge_request_merged)
-        expect(json_response.first['title']).to eq(merge_request_merged.title)
-      end
-
-      it 'returns merge_request by "iids" array' do
-        get api("/projects/#{project.id}/merge_requests", user), iids: [merge_request.iid, merge_request_closed.iid]
-
-        expect_response_ordered_exactly(merge_request_closed, merge_request)
-        expect(json_response.first['title']).to eq merge_request_closed.title
-      end
-
-      it 'matches V4 response schema' do
-        get api("/projects/#{project.id}/merge_requests", user)
-
-        expect(response).to have_gitlab_http_status(200)
-        expect(response).to match_response_schema('public_api/v4/merge_requests')
-      end
-
-      it 'returns an empty array if no issue matches milestone' do
-        get api("/projects/#{project.id}/merge_requests", user), milestone: '1.0.0'
-
-        expect_paginated_array_response
-        expect(json_response.length).to eq(0)
-      end
-
-      it 'returns an empty array if milestone does not exist' do
-        get api("/projects/#{project.id}/merge_requests", user), milestone: 'foo'
-
-        expect_paginated_array_response
-        expect(json_response.length).to eq(0)
-      end
-
-      it 'returns an array of merge requests in given milestone' do
-        get api("/projects/#{project.id}/merge_requests", user), milestone: '0.9'
-
-        expect(json_response.first['title']).to eq merge_request_closed.title
-        expect(json_response.first['id']).to eq merge_request_closed.id
-      end
-
-      it 'returns an array of merge requests matching state in milestone' do
-        get api("/projects/#{project.id}/merge_requests", user), milestone: '0.9', state: 'closed'
-
-        expect_response_ordered_exactly(merge_request_closed)
-      end
-
-      it 'returns an array of labeled merge requests' do
-        get api("/projects/#{project.id}/merge_requests?labels=#{label.title}", user)
-
-        expect_paginated_array_response
-        expect(json_response.length).to eq(1)
-        expect(json_response.first['labels']).to eq([label2.title, label.title])
-      end
-
-      it 'returns an array of labeled merge requests where all labels match' do
-        get api("/projects/#{project.id}/merge_requests?labels=#{label.title},foo,bar", user)
-
-        expect_paginated_array_response
-        expect(json_response.length).to eq(0)
-      end
-
-      it 'returns an empty array if no merge request matches labels' do
-        get api("/projects/#{project.id}/merge_requests?labels=foo,bar", user)
-
-        expect_paginated_array_response
-        expect(json_response.length).to eq(0)
-      end
-
-      it 'returns an array of labeled merge requests that are merged for a milestone' do
-        bug_label = create(:label, title: 'bug', color: '#FFAABB', project: project)
-
-        mr1 = create(:merge_request, state: "merged", source_project: project, target_project: project, milestone: milestone)
-        mr2 = create(:merge_request, state: "merged", source_project: project, target_project: project, milestone: milestone1)
-        mr3 = create(:merge_request, state: "closed", source_project: project, target_project: project, milestone: milestone1)
-        _mr = create(:merge_request, state: "merged", source_project: project, target_project: project, milestone: milestone1)
-
-        create(:label_link, label: bug_label, target: mr1)
-        create(:label_link, label: bug_label, target: mr2)
-        create(:label_link, label: bug_label, target: mr3)
-
-        get api("/projects/#{project.id}/merge_requests?labels=#{bug_label.title}&milestone=#{milestone1.title}&state=merged", user)
-
-        expect_response_ordered_exactly(mr2)
-      end
-
-      context "with ordering" do
-        let(:merge_requests) { [merge_request_merged, merge_request_closed, merge_request] }
-
-        before do
-          @mr_later = mr_with_later_created_and_updated_at_time
-          @mr_earlier = mr_with_earlier_created_and_updated_at_time
-        end
-
-        it "returns an array of merge_requests in ascending order" do
-          get api("/projects/#{project.id}/merge_requests?sort=asc", user)
-
-          expect_response_ordered_exactly(*merge_requests.sort_by { |mr| mr['created_at'] })
-        end
-
-        it "returns an array of merge_requests in descending order" do
-          get api("/projects/#{project.id}/merge_requests?sort=desc", user)
+    it "returns 404 for non public projects" do
+      project = create(:project, :private)
 
-          expect_response_ordered_exactly(*merge_requests.sort_by { |mr| mr['created_at'] }.reverse)
-        end
+      get api("/projects/#{project.id}/merge_requests")
 
-        it "returns an array of merge_requests ordered by updated_at" do
-          get api("/projects/#{project.id}/merge_requests?order_by=updated_at", user)
+      expect(response).to have_gitlab_http_status(404)
+    end
 
-          expect_response_ordered_exactly(*merge_requests.sort_by { |mr| mr['updated_at'] }.reverse)
-        end
+    it 'returns merge_request by "iids" array' do
+      get api(endpoint_path, user), iids: [merge_request.iid, merge_request_closed.iid]
 
-        it "returns an array of merge_requests ordered by created_at" do
-          get api("/projects/#{project.id}/merge_requests?order_by=created_at&sort=asc", user)
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(2)
+      expect(json_response.first['title']).to eq merge_request_closed.title
+      expect(json_response.first['id']).to eq merge_request_closed.id
+    end
+  end
 
-          expect_response_ordered_exactly(*merge_requests.sort_by { |mr| mr['created_at'] })
-        end
-      end
+  describe "GET /groups/:id/merge_requests" do
+    let!(:group) { create(:group, :public) }
+    let!(:project) { create(:project, :public, :repository, creator: user, namespace: group, only_allow_merge_if_pipeline_succeeds: false) }
+    let(:endpoint_path) { "/groups/#{group.id}/merge_requests" }
 
-      context 'source_branch param' do
-        it 'returns merge requests with the given source branch' do
-          get api('/merge_requests', user), source_branch: merge_request_closed.source_branch, state: 'all'
+    before do
+      group.add_reporter(user)
+    end
 
-          expect_response_contain_exactly(merge_request_closed, merge_request_merged)
-        end
-      end
+    it_behaves_like 'merge requests list'
 
-      context 'target_branch param' do
-        it 'returns merge requests with the given target branch' do
-          get api('/merge_requests', user), target_branch: merge_request_closed.target_branch, state: 'all'
+    context 'when have subgroups', :nested_groups do
+      let!(:group) { create(:group, :public) }
+      let!(:subgroup) { create(:group, parent: group) }
+      let!(:project) { create(:project, :public, :repository, creator: user, namespace: subgroup, only_allow_merge_if_pipeline_succeeds: false) }
 
-          expect_response_contain_exactly(merge_request_closed, merge_request_merged)
-        end
-      end
+      it_behaves_like 'merge requests list'
     end
   end
 
diff --git a/spec/support/shared_examples/requests/api/merge_requests_list.rb b/spec/support/shared_examples/requests/api/merge_requests_list.rb
new file mode 100644
index 00000000000..d5e22b8cb56
--- /dev/null
+++ b/spec/support/shared_examples/requests/api/merge_requests_list.rb
@@ -0,0 +1,280 @@
+shared_examples 'merge requests list' do
+  context 'when unauthenticated' do
+    it 'returns merge requests for public projects' do
+      get api(endpoint_path)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+    end
+  end
+
+  context 'when authenticated' do
+    it 'avoids N+1 queries' do
+      control = ActiveRecord::QueryRecorder.new do
+        get api(endpoint_path, user)
+      end
+
+      create(:merge_request, state: 'closed', milestone: milestone1, author: user, assignee: user, source_project: project, target_project: project, title: 'Test', created_at: base_time)
+
+      create(:merge_request, milestone: milestone1, author: user, assignee: user, source_project: project, target_project: project, title: 'Test', created_at: base_time)
+
+      expect do
+        get api(endpoint_path, user)
+      end.not_to exceed_query_limit(control)
+    end
+
+    it 'returns an array of all merge_requests' do
+      get api(endpoint_path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(3)
+      expect(json_response.last['title']).to eq(merge_request.title)
+      expect(json_response.last).to have_key('web_url')
+      expect(json_response.last['sha']).to eq(merge_request.diff_head_sha)
+      expect(json_response.last['merge_commit_sha']).to be_nil
+      expect(json_response.last['merge_commit_sha']).to eq(merge_request.merge_commit_sha)
+      expect(json_response.last['downvotes']).to eq(1)
+      expect(json_response.last['upvotes']).to eq(1)
+      expect(json_response.last['labels']).to eq([label2.title, label.title])
+      expect(json_response.first['title']).to eq(merge_request_merged.title)
+      expect(json_response.first['sha']).to eq(merge_request_merged.diff_head_sha)
+      expect(json_response.first['merge_commit_sha']).not_to be_nil
+      expect(json_response.first['merge_commit_sha']).to eq(merge_request_merged.merge_commit_sha)
+    end
+
+    it 'returns an array of all merge_requests using simple mode' do
+      path = endpoint_path + '?view=simple'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response.last.keys).to match_array(%w(id iid title web_url created_at description project_id state updated_at))
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(3)
+      expect(json_response.last['iid']).to eq(merge_request.iid)
+      expect(json_response.last['title']).to eq(merge_request.title)
+      expect(json_response.last).to have_key('web_url')
+      expect(json_response.first['iid']).to eq(merge_request_merged.iid)
+      expect(json_response.first['title']).to eq(merge_request_merged.title)
+      expect(json_response.first).to have_key('web_url')
+    end
+
+    it 'returns an array of all merge_requests' do
+      path = endpoint_path + '?state'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(3)
+      expect(json_response.last['title']).to eq(merge_request.title)
+    end
+
+    it 'returns an array of open merge_requests' do
+      path = endpoint_path + '?state=opened'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.last['title']).to eq(merge_request.title)
+    end
+
+    it 'returns an array of closed merge_requests' do
+      path = endpoint_path + '?state=closed'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.first['title']).to eq(merge_request_closed.title)
+    end
+
+    it 'returns an array of merged merge_requests' do
+      path = endpoint_path + '?state=merged'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to include_pagination_headers
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.first['title']).to eq(merge_request_merged.title)
+    end
+
+    it 'matches V4 response schema' do
+      get api(endpoint_path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(response).to match_response_schema('public_api/v4/merge_requests')
+    end
+
+    it 'returns an empty array if no issue matches milestone' do
+      get api(endpoint_path, user), milestone: '1.0.0'
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(0)
+    end
+
+    it 'returns an empty array if milestone does not exist' do
+      get api(endpoint_path, user), milestone: 'foo'
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(0)
+    end
+
+    it 'returns an array of merge requests in given milestone' do
+      get api(endpoint_path, user), milestone: '0.9'
+
+      expect(json_response.first['title']).to eq merge_request_closed.title
+      expect(json_response.first['id']).to eq merge_request_closed.id
+    end
+
+    it 'returns an array of merge requests matching state in milestone' do
+      get api(endpoint_path, user), milestone: '0.9', state: 'closed'
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.first['id']).to eq(merge_request_closed.id)
+    end
+
+    it 'returns an array of labeled merge requests' do
+      path = endpoint_path + "?labels=#{label.title}"
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.first['labels']).to eq([label2.title, label.title])
+    end
+
+    it 'returns an array of labeled merge requests where all labels match' do
+      path = endpoint_path + "?labels=#{label.title},foo,bar"
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(0)
+    end
+
+    it 'returns an empty array if no merge request matches labels' do
+      path = endpoint_path + '?labels=foo,bar'
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(0)
+    end
+
+    it 'returns an array of labeled merge requests that are merged for a milestone' do
+      bug_label = create(:label, title: 'bug', color: '#FFAABB', project: project)
+
+      mr1 = create(:merge_request, state: 'merged', source_project: project, target_project: project, milestone: milestone)
+      mr2 = create(:merge_request, state: 'merged', source_project: project, target_project: project, milestone: milestone1)
+      mr3 = create(:merge_request, state: 'closed', source_project: project, target_project: project, milestone: milestone1)
+      _mr = create(:merge_request, state: 'merged', source_project: project, target_project: project, milestone: milestone1)
+
+      create(:label_link, label: bug_label, target: mr1)
+      create(:label_link, label: bug_label, target: mr2)
+      create(:label_link, label: bug_label, target: mr3)
+
+      path = endpoint_path + "?labels=#{bug_label.title}&milestone=#{milestone1.title}&state=merged"
+
+      get api(path, user)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(json_response).to be_an Array
+      expect(json_response.length).to eq(1)
+      expect(json_response.first['id']).to eq(mr2.id)
+    end
+
+    context 'with ordering' do
+      before do
+        @mr_later = mr_with_later_created_and_updated_at_time
+        @mr_earlier = mr_with_earlier_created_and_updated_at_time
+      end
+
+      it 'returns an array of merge_requests in ascending order' do
+        path = endpoint_path + '?sort=asc'
+
+        get api(path, user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.length).to eq(3)
+        response_dates = json_response.map { |merge_request| merge_request['created_at'] }
+        expect(response_dates).to eq(response_dates.sort)
+      end
+
+      it 'returns an array of merge_requests in descending order' do
+        path = endpoint_path + '?sort=desc'
+
+        get api(path, user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.length).to eq(3)
+        response_dates = json_response.map { |merge_request| merge_request['created_at'] }
+        expect(response_dates).to eq(response_dates.sort.reverse)
+      end
+
+      it 'returns an array of merge_requests ordered by updated_at' do
+        path = endpoint_path + '?order_by=updated_at'
+
+        get api(path, user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.length).to eq(3)
+        response_dates = json_response.map { |merge_request| merge_request['updated_at'] }
+        expect(response_dates).to eq(response_dates.sort.reverse)
+      end
+
+      it 'returns an array of merge_requests ordered by created_at' do
+        path = endpoint_path + '?order_by=created_at&sort=asc'
+
+        get api(path, user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to include_pagination_headers
+        expect(json_response).to be_an Array
+        expect(json_response.length).to eq(3)
+        response_dates = json_response.map { |merge_request| merge_request['created_at'] }
+        expect(response_dates).to eq(response_dates.sort)
+      end
+    end
+
+    context 'source_branch param' do
+      it 'returns merge requests with the given source branch' do
+        get api(endpoint_path, user), source_branch: merge_request_closed.source_branch, state: 'all'
+
+        expect_response_contain_exactly(merge_request_closed, merge_request_merged)
+      end
+    end
+
+    context 'target_branch param' do
+      it 'returns merge requests with the given target branch' do
+        get api(endpoint_path, user), target_branch: merge_request_closed.target_branch, state: 'all'
+
+        expect_response_contain_exactly(merge_request_closed, merge_request_merged)
+      end
+    end
+  end
+end