Add hint text to numeric question

app/views/questions/_numeric_question.html.erb

@@ -1,4 +1,7 @@
 <div class="govuk-form-group">
     <label for="numeric_input"><%= label %></label>
+    <div id="numeric_hint" class="govuk-hint">
+        <%= hint_text %>
+    </div>
     <input id="numeric_input" class="govuk-input govuk-input--width-20" type="number" min=<%= minimum %> max=<%= maximum %> />
 </div>

spec/views/questions/_numeric_question.html.erb_spec.rb

@@ -1,25 +1,31 @@
-describe 'questions/_numeric_question.html.erb' do
-    context 'when given a label and value constraints' do
-        let(:label) { "Test Label" }
-        let(:min) { "1" }
-        let(:max) { "150" }
-        let(:locals) { {label: label, minimum: min, maximum: max} }
+describe "questions/_numeric_question.html.erb" do
+  context "when given a label, value constraints and hint text" do
+    let(:label) { "Test Label" }
+    let(:min) { "1" }
+    let(:max) { "150" }
+    let(:hint_text) { "Some text that describes the question in more detail" }
+    let(:locals) { { label: label, minimum: min, maximum: max, hint_text: hint_text } }
 
-        before(:each) do
-            render :partial => 'numeric_question', locals: locals
-        end
+    before(:each) do
+      render partial: "numeric_question", locals: locals
+    end
 
-        it 'displays a numeric entry field with a label' do     
-            expect(rendered).to have_selector('//input[@type="number"]')
-            expect(rendered).to have_selector("//label[contains('#{label}')]")
-        end
+    it "displays a numeric entry field with a label" do
+      expect(rendered).to have_selector('//input[@type="number"]')
+      expect(rendered).to have_selector("//label[contains('#{label}')]")
+    end
 
-        it 'validates for a given minimum input' do
-            expect(rendered).to have_selector("//input[@min=#{min}]")
-        end
+    it "validates for a given minimum input" do
+      expect(rendered).to have_selector("//input[@min=#{min}]")
+    end
+
+    it "validates for a given maximum input" do
+      expect(rendered).to have_selector("//input[@max=#{max}]")
+    end
 
-        it 'validates for a given maximum input' do
-            expect(rendered).to have_selector("//input[@max=#{max}]")
-        end
+    it "displays hint text" do
+      expect(rendered).to have_selector("//div[@class='govuk-hint']")
+      expect(rendered).to have_css("#numeric_hint", text: hint_text.to_s)
     end
-end
+  end
+end