Add hint text for joint question after 2024 (#2163)

app/models/form/lettings/questions/joint.rb

@@ -6,7 +6,7 @@ class Form::Lettings::Questions::Joint < ::Form::Question
     @header = "Is this a joint tenancy?"
     @type = "radio"
     @check_answers_card_number = 0
-    @hint_text = ""
+    @hint_text = form.start_year_after_2024? ? "This is where two or more people are named on the tenancy agreement" : ""
     @answer_options = ANSWER_OPTIONS
     @question_number = 25
   end

spec/models/form/lettings/questions/joint_spec.rb

@@ -0,0 +1,64 @@
+require "rails_helper"
+
+RSpec.describe Form::Lettings::Questions::Joint, type: :model do
+  subject(:question) { described_class.new(question_id, question_definition, page) }
+
+  let(:question_id) { nil }
+  let(:question_definition) { nil }
+  let(:page) { instance_double(Form::Page) }
+  let(:subsection) { instance_double(Form::Subsection) }
+  let(:form) { instance_double(Form) }
+
+  before do
+    allow(form).to receive(:start_year_after_2024?).and_return(false)
+    allow(page).to receive(:subsection).and_return(subsection)
+    allow(subsection).to receive(:form).and_return(form)
+  end
+
+  it "has correct page" do
+    expect(question.page).to eq(page)
+  end
+
+  it "has the correct id" do
+    expect(question.id).to eq("joint")
+  end
+
+  it "has the correct header" do
+    expect(question.header).to eq("Is this a joint tenancy?")
+  end
+
+  it "has the correct check_answer_label" do
+    expect(question.check_answer_label).to eq("Is this a joint tenancy?")
+  end
+
+  it "has the correct type" do
+    expect(question.type).to eq("radio")
+  end
+
+  it "has the correct hint_text" do
+    expect(question.hint_text).to eq("")
+  end
+
+  it "has the correct answer_options" do
+    expect(question.answer_options).to eq({
+      "1" => { "value" => "Yes" },
+      "2" => { "value" => "No" },
+      "divider" => { "value" => "true" },
+      "3" => { "value" => "Don’t know" },
+    })
+  end
+
+  it "is not marked as derived" do
+    expect(question.derived?).to be false
+  end
+
+  context "with collection year on or after 2024" do
+    before do
+      allow(form).to receive(:start_year_after_2024?).and_return(true)
+    end
+
+    it "has the correct hint_text" do
+      expect(question.hint_text).to eq("This is where two or more people are named on the tenancy agreement")
+    end
+  end
+end