Add UpdateQualificationCertificateDate

This adds a service that makes it possible to change the qualification
certificate date of an application after it has been submitted.

app/services/update_qualification_certificate_date.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+class UpdateQualificationCertificateDate
+  include ServicePattern
+
+  def initialize(qualification:, user:, certificate_date:)
+    @qualification = qualification
+    @user = user
+    @certificate_date = certificate_date
+  end
+
+  def call
+    old_certificate_date = qualification.certificate_date
+
+    ActiveRecord::Base.transaction do
+      qualification.update!(certificate_date:)
+      create_timeline_event(old_certificate_date:)
+    end
+  end
+
+  private
+
+  attr_reader :qualification, :user, :certificate_date
+
+  delegate :application_form, to: :qualification
+
+  def create_timeline_event(old_certificate_date:)
+    CreateTimelineEvent.call(
+      "information_changed",
+      application_form:,
+      user:,
+      qualification:,
+      column_name: "certificate_date",
+      old_value: old_certificate_date.strftime("%B %Y").strip,
+      new_value: certificate_date.strftime("%B %Y").strip,
+    )
+  end
+end

spec/services/update_qualification_certificate_date_spec.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe UpdateQualificationCertificateDate do
+  let(:qualification) do
+    create(:qualification, certificate_date: Date.new(2020, 1, 1))
+  end
+  let(:application_form) { qualification.application_form }
+  let(:user) { create(:staff) }
+  let(:new_certificate_date) { Date.new(2021, 1, 1) }
+
+  subject(:call) do
+    described_class.call(
+      qualification:,
+      user:,
+      certificate_date: new_certificate_date,
+    )
+  end
+
+  it "changes the certificate date" do
+    expect { call }.to change(qualification, :certificate_date).to(
+      new_certificate_date,
+    )
+  end
+
+  it "records a timeline event" do
+    expect { call }.to have_recorded_timeline_event(
+      :information_changed,
+      creator: user,
+      application_form:,
+      qualification:,
+      column_name: "certificate_date",
+      old_value: "January 2020",
+      new_value: "January 2021",
+    )
+  end
+end