Expose iteration burnup chart time series through GraphQL

Refactored MilestoneBurnupTimeSeriesResolver into a more generic
TimeboxBurnupTimeSeriesResolver that handles both milestone and
iteration and returns time series to be rendered into
burnup/burndown charts.

doc/api/graphql/reference/gitlab_schema.graphql

@@ -8555,7 +8555,12 @@ enum IssueType {
 """
 Represents an iteration object.
 """
-type Iteration {
+type Iteration implements TimeboxBurnupTimeSeriesInterface {
+  """
+  Daily scope and completed totals for burnup charts
+  """
+  burnupTimeSeries: [BurnupChartDailyTotals!]
+
   """
   Timestamp of iteration creation
   """
@@ -10398,7 +10403,7 @@ type MetricsDashboardAnnotationEdge {
 """
 Represents a milestone.
 """
-type Milestone {
+type Milestone implements TimeboxBurnupTimeSeriesInterface {
   """
   Daily scope and completed totals for burnup charts
   """
@@ -16514,6 +16519,13 @@ Time represented in ISO 8601
 """
 scalar Time
 
+interface TimeboxBurnupTimeSeriesInterface {
+  """
+  Daily scope and completed totals for burnup charts
+  """
+  burnupTimeSeries: [BurnupChartDailyTotals!]
+}
+
 type Timelog {
   """
   Timestamp of when the time tracked was spent at. Deprecated in 12.10: Use `spentAt`

doc/api/graphql/reference/gitlab_schema.json

@@ -23567,6 +23567,28 @@
           "name": "Iteration",
           "description": "Represents an iteration object.",
           "fields": [
+            {
+              "name": "burnupTimeSeries",
+              "description": "Daily scope and completed totals for burnup charts",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "LIST",
+                "name": null,
+                "ofType": {
+                  "kind": "NON_NULL",
+                  "name": null,
+                  "ofType": {
+                    "kind": "OBJECT",
+                    "name": "BurnupChartDailyTotals",
+                    "ofType": null
+                  }
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            },
             {
               "name": "createdAt",
               "description": "Timestamp of iteration creation",
@@ -23798,7 +23820,11 @@
           ],
           "inputFields": null,
           "interfaces": [
-
+            {
+              "kind": "INTERFACE",
+              "name": "TimeboxBurnupTimeSeriesInterface",
+              "ofType": null
+            }
           ],
           "enumValues": null,
           "possibleTypes": null
@@ -29142,7 +29168,11 @@
           ],
           "inputFields": null,
           "interfaces": [
-
+            {
+              "kind": "INTERFACE",
+              "name": "TimeboxBurnupTimeSeriesInterface",
+              "ofType": null
+            }
           ],
           "enumValues": null,
           "possibleTypes": null
@@ -48418,6 +48448,50 @@
           "enumValues": null,
           "possibleTypes": null
         },
+        {
+          "kind": "INTERFACE",
+          "name": "TimeboxBurnupTimeSeriesInterface",
+          "description": null,
+          "fields": [
+            {
+              "name": "burnupTimeSeries",
+              "description": "Daily scope and completed totals for burnup charts",
+              "args": [
+
+              ],
+              "type": {
+                "kind": "LIST",
+                "name": null,
+                "ofType": {
+                  "kind": "NON_NULL",
+                  "name": null,
+                  "ofType": {
+                    "kind": "OBJECT",
+                    "name": "BurnupChartDailyTotals",
+                    "ofType": null
+                  }
+                }
+              },
+              "isDeprecated": false,
+              "deprecationReason": null
+            }
+          ],
+          "inputFields": null,
+          "interfaces": null,
+          "enumValues": null,
+          "possibleTypes": [
+            {
+              "kind": "OBJECT",
+              "name": "Iteration",
+              "ofType": null
+            },
+            {
+              "kind": "OBJECT",
+              "name": "Milestone",
+              "ofType": null
+            }
+          ]
+        },
         {
           "kind": "OBJECT",
           "name": "Timelog",

doc/api/graphql/reference/index.md

@@ -1295,6 +1295,7 @@ Represents an iteration object.
 
 | Field | Type | Description |
 | ----- | ---- | ----------- |
+| `burnupTimeSeries` | BurnupChartDailyTotals! => Array | Daily scope and completed totals for burnup charts |
 | `createdAt` | Time! | Timestamp of iteration creation |
 | `description` | String | Description of the iteration |
 | `descriptionHtml` | String | The GitLab Flavored Markdown rendering of `description` |

ee/app/graphql/ee/types/milestone_type.rb

@@ -6,10 +6,7 @@ module EE
       extend ActiveSupport::Concern
 
       prepended do
-        field :burnup_time_series, [::Types::BurnupChartDailyTotalsType], null: true,
-              resolver: ::Resolvers::MilestoneBurnupTimeSeriesResolver,
-              description: 'Daily scope and completed totals for burnup charts',
-              complexity: 175
+        implements ::Types::TimeboxBurnupTimeSeriesInterface
       end
     end
   end

ee/app/graphql/resolvers/milestone_burnup_time_series_resolver.rb → ee/app/graphql/resolvers/timebox_burnup_time_series_resolver.rb

 # frozen_string_literal: true
 
 module Resolvers
-  class MilestoneBurnupTimeSeriesResolver < BaseResolver
+  class TimeboxBurnupTimeSeriesResolver < BaseResolver
     type [Types::BurnupChartDailyTotalsType], null: true
 
-    alias_method :milestone, :synchronized_object
+    alias_method :timebox, :synchronized_object
 
     def resolve(*args)
-      return [] unless milestone.burnup_charts_available?
+      return [] unless timebox.burnup_charts_available?
 
-      response = TimeboxBurnupChartService.new(milestone).execute
+      response = TimeboxBurnupChartService.new(timebox).execute
 
       raise GraphQL::ExecutionError, response.message if response.error?
 

ee/app/graphql/types/iteration_type.rb

@@ -9,6 +9,8 @@ module Types
 
     authorize :read_iteration
 
+    implements ::Types::TimeboxBurnupTimeSeriesInterface
+
     field :id, GraphQL::ID_TYPE, null: false,
           description: 'ID of the iteration'
 

ee/app/graphql/types/timebox_burnup_time_series_interface.rb

+# frozen_string_literal: true
+
+module Types
+  module TimeboxBurnupTimeSeriesInterface
+    include BaseInterface
+
+    field :burnup_time_series, [::Types::BurnupChartDailyTotalsType], null: true,
+          resolver: ::Resolvers::TimeboxBurnupTimeSeriesResolver,
+          description: 'Daily scope and completed totals for burnup charts',
+          complexity: 175
+  end
+end

ee/spec/graphql/resolvers/milestone_burnup_time_series_resolver_spec.rb

-# frozen_string_literal: true
-
-require 'spec_helper'
-
-RSpec.describe Resolvers::MilestoneBurnupTimeSeriesResolver do
-  include GraphqlHelpers
-
-  let_it_be(:project) { create(:project) }
-  let_it_be(:milestone) { create(:milestone, project: project, start_date: '2020-01-01', due_date: '2020-01-15') }
-  let_it_be(:issues) { create_list(:issue, 2, project: project) }
-
-  before_all do
-    create(:resource_milestone_event, issue: issues[0], milestone: milestone, action: :add, created_at: '2020-01-05')
-    create(:resource_milestone_event, issue: issues[1], milestone: milestone, action: :add, created_at: '2020-01-10')
-  end
-
-  before do
-    stub_licensed_features(milestone_charts: true, issue_weights: true)
-  end
-
-  subject { resolve(described_class, obj: milestone) }
-
-  context 'when the feature flag is disabled' do
-    before do
-      stub_feature_flags(burnup_charts: false)
-    end
-
-    it 'returns empty data' do
-      expect(subject).to be_empty
-    end
-  end
-
-  context 'when the feature flag is enabled' do
-    before do
-      stub_feature_flags(burnup_charts: true)
-    end
-
-    it 'returns burnup chart data' do
-      expect(subject).to eq([
-        {
-          date: Date.parse('2020-01-05'),
-          scope_count: 1,
-          scope_weight: 0,
-          completed_count: 0,
-          completed_weight: 0
-        },
-        {
-          date: Date.parse('2020-01-10'),
-          scope_count: 2,
-          scope_weight: 0,
-          completed_count: 0,
-          completed_weight: 0
-        }
-      ])
-    end
-
-    context 'when the service returns an error' do
-      before do
-        stub_const('TimeboxBurnupChartService::EVENT_COUNT_LIMIT', 1)
-      end
-
-      it 'raises a GraphQL exception' do
-        expect { subject }.to raise_error(GraphQL::ExecutionError, 'Burnup chart could not be generated due to too many events')
-      end
-    end
-  end
-end

ee/spec/graphql/resolvers/timebox_burnup_time_series_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::TimeboxBurnupTimeSeriesResolver do
+  include GraphqlHelpers
+
+  let_it_be(:group) { create(:group) }
+  let_it_be(:project) { create(:project, group: group) }
+  let_it_be(:issues) { create_list(:issue, 2, project: project) }
+  let_it_be(:start_date) { Date.today }
+  let_it_be(:due_date) { start_date + 2.weeks }
+
+  before do
+    stub_licensed_features(milestone_charts: true, issue_weights: true, iterations: true)
+  end
+
+  RSpec.shared_examples 'timebox time series' do
+    subject { resolve(described_class, obj: timebox) }
+
+    context 'when the feature flag is disabled' do
+      before do
+        stub_feature_flags(burnup_charts: false, iteration_charts: false)
+      end
+
+      it 'returns empty data' do
+        expect(subject).to be_empty
+      end
+    end
+
+    context 'when the feature flag is enabled' do
+      before do
+        stub_feature_flags(burnup_charts: true)
+      end
+
+      it 'returns burnup chart data' do
+        expect(subject).to eq([
+                                {
+                                  date: start_date + 4.days,
+                                  scope_count: 1,
+                                  scope_weight: 0,
+                                  completed_count: 0,
+                                  completed_weight: 0
+                                },
+                                {
+                                  date: start_date + 9.days,
+                                  scope_count: 2,
+                                  scope_weight: 0,
+                                  completed_count: 0,
+                                  completed_weight: 0
+                                }
+                              ])
+      end
+
+      context 'when the service returns an error' do
+        before do
+          stub_const('TimeboxBurnupChartService::EVENT_COUNT_LIMIT', 1)
+        end
+
+        it 'raises a GraphQL exception' do
+          expect { subject }.to raise_error(GraphQL::ExecutionError, 'Burnup chart could not be generated due to too many events')
+        end
+      end
+    end
+  end
+
+  context 'when timebox is a milestone' do
+    let_it_be(:timebox) { create(:milestone, project: project, start_date: start_date, due_date: due_date) }
+
+    before_all do
+      create(:resource_milestone_event, issue: issues[0], milestone: timebox, action: :add, created_at: start_date + 4.days)
+      create(:resource_milestone_event, issue: issues[1], milestone: timebox, action: :add, created_at: start_date + 9.days)
+    end
+
+    it_behaves_like 'timebox time series'
+  end
+
+  context 'when timebox is an iteration' do
+    let_it_be(:timebox) { create(:iteration, group: group, start_date: start_date, due_date: due_date) }
+
+    before_all do
+      create(:resource_iteration_event, issue: issues[0], iteration: timebox, action: :add, created_at: start_date + 4.days)
+      create(:resource_iteration_event, issue: issues[1], iteration: timebox, action: :add, created_at: start_date + 9.days)
+    end
+
+    it_behaves_like 'timebox time series'
+  end
+end

ee/spec/graphql/types/iteration_type_spec.rb

@@ -6,4 +6,13 @@ RSpec.describe GitlabSchema.types['Iteration'] do
   it { expect(described_class.graphql_name).to eq('Iteration') }
 
   it { expect(described_class).to require_graphql_authorizations(:read_iteration) }
+
+  it 'has the expected fields' do
+    expected_fields = %w[
+      id id title description state web_path web_url scoped_path scoped_url
+      due_date start_date created_at updated_at burnup_time_series
+    ]
+
+    expect(described_class).to have_graphql_fields(*expected_fields).at_least
+  end
 end