Approvals API endpoint:

- Added endpoint to retrieve approval status of MR
- Added endpoint to approve MR

doc/api/merge_requests.md

@@ -485,6 +485,104 @@ Parameters:
 }
 ```
 
+## Merge Request Approvals
+
+>**Note:** This API endpoint is only available on 8.9 EE and above.
+
+You can request information about a merge request's approval status using the
+following endpoint:
+
+```
+GET /projects/:id/merge_requests/:merge_request_id/approvals
+```
+
+**Parameters:**
+
+- id (required)                         - The ID of a project
+- merge_request_id (required)           - ID of MR
+
+```json
+{
+  "id": 5,
+  "iid": 5,
+  "project_id": 1,
+  "title": "Approvals API",
+  "description": "Test",
+  "state": "opened",
+  "created_at": "2016-06-08T00:19:52.638Z",
+  "updated_at": "2016-06-08T21:20:42.470Z",
+  "merge_status": "can_be_merged",
+  "approvals_required": 2,
+  "approvals_missing": 1,
+  "approved_by": [
+    {
+      "user": {
+        "name": "Administrator",
+        "username": "root",
+        "id": 1,
+        "state": "active",
+        "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=80\u0026d=identicon",
+        "web_url": "http://localhost:3000/u/root"
+      }
+    }
+  ]
+}
+```
+
+## Approve Merge Request
+
+>**Note:** This API endpoint is only available on 8.9 EE and above.
+
+If you are allowed to, you can approve a merge request using the following 
+endpoint:
+
+```
+POST /projects/:id/merge_requests/:merge_request_id/approvals
+```
+
+**Parameters:**
+
+- id (required)                         - The ID of a project
+- merge_request_id (required)           - ID of MR
+
+```json
+{
+  "id": 5,
+  "iid": 5,
+  "project_id": 1,
+  "title": "Approvals API",
+  "description": "Test",
+  "state": "opened",
+  "created_at": "2016-06-08T00:19:52.638Z",
+  "updated_at": "2016-06-09T21:32:14.105Z",
+  "merge_status": "can_be_merged",
+  "approvals_required": 2,
+  "approvals_missing": 0,
+  "approved_by": [
+    {
+      "user": {
+        "name": "Administrator",
+        "username": "root",
+        "id": 1,
+        "state": "active",
+        "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=80\u0026d=identicon",
+        "web_url": "http://localhost:3000/u/root"
+      }
+    },
+    {
+      "user": {
+        "name": "Nico Cartwright",
+        "username": "ryley",
+        "id": 2,
+        "state": "active",
+        "avatar_url": "http://www.gravatar.com/avatar/cf7ad14b34162a76d593e3affca2adca?s=80\u0026d=identicon",
+        "web_url": "http://localhost:3000/u/ryley"
+      }
+    }
+  ]
+}
+```
+
 ## Cancel Merge When Build Succeeds
 
 If successful you'll get `200 OK`.

lib/api/entities.rb

@@ -216,6 +216,21 @@ module API
       end
     end
 
+    class Approvals < Grape::Entity
+      expose :user, as: :user, using: Entities::UserBasic
+    end
+
+    class MergeRequestApprovals < ProjectEntity
+      expose :merge_status
+      expose :approvals_required do |merge_request, _|
+        merge_request.approvals_required
+      end
+      expose :approvals_missing do |merge_request, _|
+        merge_request.approvals_left
+      end
+      expose :approvals, as: :approved_by, using: Entities::Approvals
+    end
+
     class SSHKey < Grape::Entity
       expose :id, :title, :key, :created_at
     end

lib/api/merge_requests.rb

@@ -332,6 +332,39 @@ module API
           issues = ::Kaminari.paginate_array(merge_request.closes_issues(current_user))
           present paginate(issues), with: Entities::Issue, current_user: current_user
         end
+
+        # Get the status of the merge request's approvals
+        # Parameters:
+        #   id (required)                         - The ID of a project
+        #   merge_request_id (required)           - ID of MR
+        # Examples:
+        #   GET /projects/:id/merge_requests/:merge_request_id/approvals
+        #
+        get "#{path}/approvals" do
+          merge_request = user_project.merge_requests.find(params[:merge_request_id])
+
+          authorize! :read_merge_request, merge_request
+          present merge_request, with: Entities::MergeRequestApprovals, current_user: current_user
+        end
+
+        # Approve a merge request
+        # Parameters:
+        #   id (required)                         - The ID of a project
+        #   merge_request_id (required)           - ID of MR
+        # Examples:
+        #   POST /projects/:id/merge_requests/:merge_request_id/approvals
+        #
+        post "#{path}/approve" do
+          merge_request = user_project.merge_requests.find(params[:merge_request_id])
+
+          unauthorized! unless merge_request.can_approve?(current_user)
+
+          ::MergeRequests::ApprovalService.
+            new(user_project, current_user).
+            execute(merge_request)
+
+          present merge_request, with: Entities::MergeRequestApprovals, current_user: current_user
+        end
       end
     end
   end

spec/requests/api/merge_requests_spec.rb

@@ -598,6 +598,28 @@ describe API::API, api: true  do
     end
   end
 
+  describe 'GET :id/merge_requests/:merge_request_id/approvals' do
+    it 'retrieves the approval status' do
+      project.update_attribute(:approvals_before_merge, 2)
+
+      get api("/projects/#{project.id}/merge_requests/#{merge_request.id}/approvals", user)
+
+      expect(response.status).to eq(200)
+      expect(json_response['approvals_required']).to eq 2
+    end
+  end
+
+  describe 'POST :id/merge_requests/:merge_request_id/approve' do
+    it 'approves the merge request' do
+      project.update_attribute(:approvals_before_merge, 2)
+
+      post api("/projects/#{project.id}/merge_requests/#{merge_request.id}/approve", user)
+
+      expect(response.status).to eq(201)
+      expect(json_response['approvals_required']).to eq 1
+    end
+  end
+
   def mr_with_later_created_and_updated_at_time
     merge_request
     merge_request.created_at += 1.hour