Improve invoice_form_test

test/integration/invoice_form_test.rb

@@ -43,13 +43,8 @@ class NewInvoiceTest < ActionDispatch::IntegrationTest
   end
 
   test 'sets calculated total on page load' do
-    expected_total = '%.2f' % (billable_hours * rate).round(2)
-
-    text_on_page =
-      find('#invoice_total_amount')
-      .text
-      .delete("'")
-      .delete('&#39;')
+    expected_total = delimited_number(billable_hours * rate)  
+    text_on_page = find('#invoice_total_amount').text
 
     assert_match expected_total, text_on_page
   end
@@ -213,4 +208,12 @@ def assert_checkboxes(checkboxes, models, checked = models)
       send assertion, checkboxes.find { |checkbox| checkbox.value == model.id.to_s }.checked?
     end
   end
+
+  def delimited_number(number)
+    ActiveSupport::NumberHelper.number_to_rounded(
+      number,
+      precision: 2,
+      delimiter: "'"
+    )
+  end
 end