Add frontend fixtures for deployment frequency API

This commit adds frontend fixtures that represent calls to the
/projects/:id/analytics/deployment_frequency REST endpoint.

spec/frontend/fixtures/project_analytics.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Project Analytics (JavaScript fixtures)' do
+  include ApiHelpers
+  include JavaScriptFixturesHelpers
+
+  let_it_be(:reporter) { create(:user) }
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:environment) { create(:environment, project: project, name: 'production') }
+
+  let!(:deployments) do
+    [
+      1.minute.ago,
+      2.days.ago,
+      3.days.ago,
+      3.days.ago,
+      3.days.ago,
+      8.days.ago,
+      32.days.ago,
+      91.days.ago
+    ].map do |finished_at|
+      create(:deployment,
+        :success,
+        project: project,
+        environment: environment,
+        finished_at: finished_at)
+    end
+  end
+
+  before do
+    stub_licensed_features(project_activity_analytics: true)
+    project.add_reporter(reporter)
+    sign_in(reporter)
+  end
+
+  after(:all) do
+    remove_repository(project)
+  end
+
+  describe API::Analytics::ProjectDeploymentFrequency, type: :request do
+    before(:all) do
+      clean_frontend_fixtures('api/project_analytics/')
+    end
+
+    let(:shared_params) { { environment: environment.name, interval: 'daily' } }
+
+    def make_request(additional_query_params:)
+      params = shared_params.merge(additional_query_params)
+      get api("/projects/#{project.id}/analytics/deployment_frequency?#{params.to_query}", reporter)
+    end
+
+    it 'api/project_analytics/daily_deployment_frequencies_for_last_week.json' do
+      make_request(additional_query_params: { from: 1.week.ago })
+      expect(response).to be_successful
+    end
+
+    it 'api/project_analytics/daily_deployment_frequencies_for_last_month.json' do
+      make_request(additional_query_params: { from: 1.month.ago })
+      expect(response).to be_successful
+    end
+
+    it 'api/project_analytics/daily_deployment_frequencies_for_last_90_days.json' do
+      make_request(additional_query_params: { from: 90.days.ago })
+      expect(response).to be_successful
+    end
+  end
+end