Allow to delete epic boards

Adds GraphQL mutation and epic board service for destroying
epic boards.

app/services/boards/destroy_service.rb

@@ -3,7 +3,7 @@
 module Boards
   class DestroyService < Boards::BaseService
     def execute(board)
-      if parent.boards.size == 1
+      if boards.size == 1
         return ServiceResponse.error(message: "The board could not be deleted, because the parent doesn't have any other boards.")
       end
 
@@ -11,5 +11,11 @@ module Boards
 
       ServiceResponse.success
     end
+
+    private
+
+    def boards
+      parent.boards
+    end
   end
 end

doc/api/graphql/reference/index.md

@@ -2372,6 +2372,16 @@ Autogenerated return type of DestroyContainerRepositoryTags.
 | `deletedTagNames` | [`[String!]!`](#string) | Deleted container repository tags. |
 | `errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
 
+### `DestroyEpicBoardPayload`
+
+Autogenerated return type of DestroyEpicBoard.
+
+| Field | Type | Description |
+| ----- | ---- | ----------- |
+| `clientMutationId` | [`String`](#string) | A unique identifier for the client performing the mutation. |
+| `epicBoard` | [`EpicBoard`](#epicboard) | Epic board after mutation. |
+| `errors` | [`[String!]!`](#string) | Errors encountered during execution of the mutation. |
+
 ### `DestroyNotePayload`
 
 Autogenerated return type of DestroyNote.

ee/app/graphql/ee/types/mutation_type.rb

@@ -39,8 +39,9 @@ module EE
         mount_mutation ::Mutations::Boards::Update
         mount_mutation ::Mutations::Boards::UpdateEpicUserPreferences
         mount_mutation ::Mutations::Boards::EpicBoards::Create
-        mount_mutation ::Mutations::Boards::EpicBoards::Update
+        mount_mutation ::Mutations::Boards::EpicBoards::Destroy
         mount_mutation ::Mutations::Boards::EpicBoards::EpicMoveList
+        mount_mutation ::Mutations::Boards::EpicBoards::Update
         mount_mutation ::Mutations::Boards::EpicLists::Create
         mount_mutation ::Mutations::Boards::Lists::UpdateLimitMetrics
         mount_mutation ::Mutations::InstanceSecurityDashboard::AddProject

ee/app/graphql/mutations/boards/epic_boards/destroy.rb

+# frozen_string_literal: true
+
+module Mutations
+  module Boards
+    module EpicBoards
+      class Destroy < ::Mutations::BaseMutation
+        graphql_name 'DestroyEpicBoard'
+
+        field :epic_board,
+              Types::Boards::EpicBoardType,
+              null: true,
+              description: 'Epic board after mutation.'
+
+        argument :id,
+                 ::Types::GlobalIDType[::Boards::EpicBoard],
+                 required: true,
+                 description: 'Global ID of the board to destroy.'
+
+        authorize :admin_epic_board
+
+        def resolve(id:)
+          board = authorized_find!(id: id)
+
+          response = ::Boards::EpicBoards::DestroyService.new(board.resource_parent, current_user).execute(board)
+
+          {
+            epic_board: response.success? ? nil : board,
+            errors: response.errors
+          }
+        end
+
+        private
+
+        def find_object(id:)
+          GitlabSchema.find_by_gid(id)
+        end
+      end
+    end
+  end
+end

ee/app/services/boards/epic_boards/destroy_service.rb

+# frozen_string_literal: true
+
+module Boards
+  module EpicBoards
+    class DestroyService < ::Boards::DestroyService
+      extend ::Gitlab::Utils::Override
+
+      override :boards
+      def boards
+        parent.epic_boards
+      end
+    end
+  end
+end

ee/spec/graphql/mutations/boards/epic_boards/destroy_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::Mutations::Boards::EpicBoards::Destroy do
+  include GraphqlHelpers
+
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:group) { create(:group, :private) }
+  let_it_be_with_reload(:board) { create(:epic_board, group: group) }
+  let_it_be(:another_board) { create(:epic_board, group: group) }
+
+  let(:mutation) { described_class.new(object: nil, context: { current_user: current_user }, field: nil) }
+
+  subject { mutation.resolve(id: board.to_global_id) }
+
+  context 'field tests' do
+    subject { described_class }
+
+    it { is_expected.to have_graphql_arguments(:id) }
+    it { is_expected.to have_graphql_fields(:epic_board).at_least }
+  end
+
+  before do
+    stub_licensed_features(epics: true)
+  end
+
+  it 'raises error when user does not have permission to destroy the board' do
+    expect { subject }
+      .to raise_error(Gitlab::Graphql::Errors::ResourceNotAvailable)
+  end
+
+  context 'when user has permission to destroy the board' do
+    before do
+      group.add_reporter(current_user)
+    end
+
+    it 'destroys the epic board' do
+      result = mutation.resolve(id: board.to_global_id)
+
+      expect(result[:errors]).to be_empty
+      expect(result[:epic_board]).to be_nil
+    end
+  end
+end

ee/spec/requests/api/graphql/mutations/boards/epic_boards/destroy_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Mutations::Boards::EpicBoards::Destroy do
+  include GraphqlHelpers
+
+  let_it_be_with_reload(:current_user) { create(:user) }
+  let_it_be_with_reload(:group) { create(:group) }
+  let_it_be(:board) { create(:epic_board, group: group) }
+  let_it_be(:other_board) { create(:epic_board, group: group) }
+
+  let(:mutation) do
+    variables = {
+      id: board.to_global_id.to_s
+    }
+
+    graphql_mutation(:destroy_epic_board, variables)
+  end
+
+  subject { post_graphql_mutation(mutation, current_user: current_user) }
+
+  def mutation_response
+    graphql_mutation_response(:destroy_epic_board)
+  end
+
+  before do
+    stub_licensed_features(epics: true)
+  end
+
+  context 'when the user does not have permission' do
+    it_behaves_like 'a mutation that returns a top-level access error'
+
+    it 'does not destroy the board' do
+      expect { subject }.not_to change { ::Boards::EpicBoard.count }
+    end
+  end
+
+  context 'when the user has permission' do
+    before do
+      group.add_developer(current_user)
+    end
+
+    context 'when everything is ok' do
+      it 'destroys the board' do
+        expect { subject }.to change { ::Boards::EpicBoard.count }.by(-1)
+      end
+
+      it 'returns an empty board' do
+        post_graphql_mutation(mutation, current_user: current_user)
+
+        expect(mutation_response).to have_key('epicBoard')
+        expect(mutation_response['epicBoard']).to be_nil
+      end
+    end
+
+    context 'when there is only 1 board for the parent' do
+      before do
+        other_board.destroy!
+      end
+
+      it 'does not destroy the board' do
+        expect { subject }.not_to change { ::Boards::EpicBoard.count }
+      end
+
+      it 'returns an error and not nil board' do
+        subject
+
+        expect(mutation_response['errors']).not_to be_empty
+        expect(mutation_response['epicBoard']).not_to be_nil
+      end
+    end
+  end
+end

ee/spec/services/boards/destroy_service_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Boards::DestroyService do
-  describe '#execute' do
-    let_it_be(:project) { create(:project) }
-    let_it_be(:group) { create(:group) }
-
-    shared_examples 'remove the board' do |parent_name|
-      let(:parent) { public_send(parent_name) }
-      let!(:board) { create(:board, parent_name => parent) }
-
-      subject(:service) { described_class.new(parent, double) }
-
-      context "when #{parent_name} have more than one board" do
-        it "removes board from #{parent_name}" do
-          create(:board, parent_name => parent)
-
-          expect do
-            expect(service.execute(board)).to be_success
-          end.to change(parent.boards, :count).by(-1)
-        end
-      end
-
-      context "when #{parent_name} have one board" do
-        it "does not remove board from #{parent_name}" do
-          expect do
-            expect(service.execute(board)).to be_error
-          end.not_to change(parent.boards, :count)
-        end
-      end
-    end
-
-    it_behaves_like 'remove the board', :group
-    it_behaves_like 'remove the board', :project
-  end
-end

ee/spec/services/boards/epic_boards/destroy_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Boards::EpicBoards::DestroyService do
+  let_it_be(:parent) { create(:group) }
+  let(:boards) { parent.epic_boards }
+  let(:board_factory) { :epic_board }
+
+  it_behaves_like 'board destroy service'
+end

spec/services/boards/destroy_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Boards::DestroyService do
+  context 'with project board' do
+    let_it_be(:parent) { create(:project) }
+    let(:boards) { parent.boards }
+    let(:board_factory) { :board }
+
+    it_behaves_like 'board destroy service'
+  end
+
+  context 'with group board' do
+    let_it_be(:parent) { create(:group) }
+    let(:boards) { parent.boards }
+    let(:board_factory) { :board }
+
+    it_behaves_like 'board destroy service'
+  end
+end

spec/support/shared_examples/boards/destroy_service_shared_examples.rb

+# frozen_string_literal: true
+
+RSpec.shared_examples 'board destroy service' do
+  describe '#execute' do
+    let(:parent_type) { parent.is_a?(Project) ? :project : :group }
+    let!(:board) { create(board_factory, parent_type => parent) }
+
+    subject(:service) { described_class.new(parent, double) }
+
+    context 'when there is more than one board' do
+      let!(:board2) { create(board_factory, parent_type => parent) }
+
+      it 'destroys the board' do
+        create(board_factory, parent_type => parent)
+
+        expect do
+          expect(service.execute(board)).to be_success
+        end.to change(boards, :count).by(-1)
+      end
+    end
+
+    context 'when there is only one board' do
+      it 'does not remove board' do
+        expect do
+          expect(service.execute(board)).to be_error
+        end.not_to change(boards, :count)
+      end
+    end
+  end
+end