Refactor coverage finder dates

This commit moves our business logic to fetch daily coverage data
by dates in our new finder. We will now use default dates in case
our params being sent by the frontend are nil.

app/controllers/projects/ci/daily_build_group_report_results_controller.rb

 # frozen_string_literal: true
 
 class Projects::Ci::DailyBuildGroupReportResultsController < Projects::ApplicationController
-  include Gitlab::Utils::StrongMemoize
-
-  REPORT_WINDOW = 90.days
-
   before_action :authorize_read_build_report_results!
   before_action :validate_param_type!
 
@@ -49,28 +45,13 @@ class Projects::Ci::DailyBuildGroupReportResultsController < Projects::Applicati
     {
       project: project,
       coverage: true,
-      start_date: start_date,
-      end_date: end_date,
+      start_date: params[:start_date],
+      end_date: params[:end_date],
       ref_path: params[:ref_path],
       sort: true
     }
   end
 
-  def start_date
-    strong_memoize(:start_date) do
-      start_date = Date.parse(params.require(:start_date))
-
-      # The start_date cannot be older than `end_date - 90 days`
-      [start_date, end_date - REPORT_WINDOW].max
-    end
-  end
-
-  def end_date
-    strong_memoize(:end_date) do
-      Date.parse(params.require(:end_date))
-    end
-  end
-
   def allowed_param_types
     Ci::DailyBuildGroupReportResult::PARAM_TYPES
   end

app/controllers/projects/graphs_controller.rb

@@ -62,7 +62,7 @@ class Projects::GraphsController < Projects::ApplicationController
     return unless can?(current_user, :read_build_report_results, project)
 
     date_today = Date.current
-    report_window = Projects::Ci::DailyBuildGroupReportResultsController::REPORT_WINDOW
+    report_window = ::Ci::DailyBuildGroupReportResultsFinder::REPORT_WINDOW
 
     @daily_coverage_options = {
       base_params: {

app/finders/ci/daily_build_group_report_results_finder.rb

@@ -11,8 +11,8 @@
 #     group: integer
 #     coverage: boolean
 #     ref_path: string
-#     start_date: date
-#     end_date: date
+#     start_date: string
+#     end_date: string
 #     sort: boolean
 #     limit: integer
 
@@ -21,6 +21,8 @@ module Ci
     include Gitlab::Allowable
 
     MAX_ITEMS = 1_000
+    REPORT_WINDOW = 90.days
+    DATE_FORMAT_ALLOWED = '%Y-%m-%d'
 
     attr_reader :params, :current_user
 
@@ -62,7 +64,7 @@ module Ci
     end
 
     def by_dates(items)
-      params[:start_date].present? && params[:end_date].present? ? items.by_dates(params[:start_date], params[:end_date]) : items
+      params[:start_date].present? && params[:end_date].present? ? items.by_dates(start_date, end_date) : items
     end
 
     def sort(items)
@@ -80,6 +82,17 @@ module Ci
 
       [params[:limit].to_i, MAX_ITEMS].min
     end
+
+    def start_date
+      start_date = Date.strptime(params[:start_date], DATE_FORMAT_ALLOWED) rescue REPORT_WINDOW.ago.to_date
+
+      # The start_date cannot be older than `end_date - 90 days`
+      [start_date, end_date - REPORT_WINDOW].max
+    end
+
+    def end_date
+      Date.strptime(params[:end_date], DATE_FORMAT_ALLOWED) rescue Date.current
+    end
   end
 end
 

ee/app/controllers/groups/analytics/coverage_reports_controller.rb

@@ -42,8 +42,8 @@ class Groups::Analytics::CoverageReportsController < Groups::Analytics::Applicat
     {
       group: @group,
       coverage: true,
-      start_date: Date.parse(params.require(:start_date)),
-      end_date: Date.parse(params.require(:end_date)),
+      start_date: params[:start_date],
+      end_date: params[:end_date],
       ref_path: params[:ref_path],
       sort: true
     }

spec/finders/ci/daily_build_group_report_results_finder_spec.rb

@@ -79,6 +79,25 @@ RSpec.describe Ci::DailyBuildGroupReportResultsFinder do
             ])
           end
         end
+
+        context 'when provided dates are nil' do
+          let(:start_date) { nil }
+          let(:end_date) { nil }
+          let(:rspec_coverage_4) { create_daily_coverage('rspec', 98.0, 91.days.ago.to_date.to_s) }
+
+          it 'returns all coverages from the last 90 days' do
+            expect(coverages).to match_array(
+              [
+                karma_coverage_3,
+                rspec_coverage_3,
+                karma_coverage_2,
+                rspec_coverage_2,
+                karma_coverage_1,
+                rspec_coverage_1
+              ]
+            )
+          end
+        end
       end
     end
   end