update to show an example date in the tax year of the relevant log where that year is known

app/helpers/question_view_helper.rb

@@ -13,6 +13,18 @@ module QuestionViewHelper
     }
   end
 
+  def example_date_in_tax_year_of(date)
+    return Time.zone.today if date.nil?
+
+    year = if date.month > 4 || (date.month == 4 && date.day > 5)
+             date.year
+           else
+             date.year - 1
+           end
+
+    Date.new(year, 9, 1)
+  end
+
 private
 
   def label_size(page_header, conditional)

app/views/form/_date_question.html.erb

@@ -3,7 +3,7 @@
 <%= f.govuk_date_field question.id.to_sym,
   caption: caption(caption_text, page_header, conditional),
   legend: legend(question, page_header, conditional),
-  hint: { text: question.hint_text&.html_safe || "For example, #{Time.zone.today.to_formatted_s(:govuk_date_number_month)}" },
+  hint: { text: question.hint_text&.html_safe || "For example, #{example_date_in_tax_year_of(lettings_log.startdate).to_formatted_s(:govuk_date_number_month)}" },
   width: 20,
   **stimulus_html_attributes(question) do %>
   <%= govuk_inset_text(text: question.unresolved_hint_text) if question.unresolved_hint_text.present? && @log.unresolved %>

spec/helpers/question_view_helper_spec.rb

@@ -76,4 +76,52 @@ RSpec.describe QuestionViewHelper do
       end
     end
   end
+
+  describe "#example_date_in_tax_year_of" do
+    subject(:result) { example_date_in_tax_year_of(input) }
+
+    context "when called with nil" do
+      let(:input) { nil }
+
+      it "returns the current date" do
+        expect(result).to eq(Time.zone.today)
+      end
+    end
+
+    context "when called with a date after April" do
+      calendar_year = 2030
+      let(:input) { Date.new(calendar_year, 7, 7) }
+
+      it "returns the first of September from that year" do
+        expect(result).to eq(Date.new(calendar_year, 9, 1))
+      end
+    end
+
+    context "when called with a date before April" do
+      calendar_year = 2040
+      let(:input) { Date.new(calendar_year, 2, 7) }
+
+      it "returns the first of September from the previous year" do
+        expect(result).to eq(Date.new(calendar_year - 1, 9, 1))
+      end
+    end
+
+    context "when called with a date in April after the fifth" do
+      calendar_year = 2050
+      let(:input) { Date.new(calendar_year, 4, 7) }
+
+      it "returns the first of September from that year" do
+        expect(result).to eq(Date.new(calendar_year, 9, 1))
+      end
+    end
+
+    context "when called with a date in April before the sixth" do
+      calendar_year = 2060
+      let(:input) { Date.new(calendar_year, 4, 4) }
+
+      it "returns the first of September from the previous year" do
+        expect(result).to eq(Date.new(calendar_year - 1, 9, 1))
+      end
+    end
+  end
 end