Add autocomplete helper module

This helper module adds an assertion method that can be used across
specs that test our custom autocomplete behaviours

It's used here for updating permissions tests, and will be used in the
next commit in inviting users tests when adding autocomplete to the
organisation field

test/integration/updating_permissions_for_apps_with_many_permissions_test.rb

@@ -26,26 +26,16 @@ def assert_select_permission_to_grant_with_javascript
 
     click_link "Update permissions for #{@application.name}"
 
-    @autocomplete_input = find(".autocomplete__input")
+    @autocomplete_input_element = find(".autocomplete__input")
     @select_element = find("#new_permission_id-select", visible: false)
-    assert_equal "", @autocomplete_input.value
-    assert_equal "", @select_element.value
 
-    # when I type a few characters from a permission called "adding"
-    @autocomplete_input.fill_in with: "add"
-    autocomplete_option = find(".autocomplete__option")
-
-    # the autcomplete value reflects what I typed, a matching option appears, but the select element remains empty
-    assert_equal "add", @autocomplete_input.value
-    assert_equal @new_permission_to_grant.name, autocomplete_option.text
-    assert_equal "", @select_element.value
-
-    # when I click on the matching option
-    autocomplete_option.click
-
-    # the autocomplete and select elements reflect my selection
-    assert_equal @new_permission_to_grant.name, @autocomplete_input.value
-    assert_equal @new_permission_to_grant.id.to_s, @select_element.value
+    assert_select_with_autocomplete(
+      autocomplete_input_element: @autocomplete_input_element,
+      select_element: @select_element,
+      option_text: @new_permission_to_grant.name,
+      option_value: @new_permission_to_grant.id.to_s,
+      unique_partial_string: "add",
+    )
   end
 
   context "with apps that have more than eight permissions" do

test/support/autocomplete_helpers.rb

@@ -0,0 +1,28 @@
+module AutocompleteHelpers
+  def assert_select_with_autocomplete(
+    autocomplete_input_element:,
+    select_element:,
+    option_text:,
+    option_value:,
+    unique_partial_string:
+  )
+    assert_equal "", autocomplete_input_element.value
+    assert_equal "", select_element.value
+
+    # when I type a few characters from the option that are unique to that option
+    autocomplete_input_element.fill_in with: unique_partial_string
+    autocomplete_option = find(".autocomplete__option")
+
+    # the autcomplete value reflects what I typed, a matching option appears, but the select element remains empty
+    assert_equal unique_partial_string, autocomplete_input_element.value
+    assert_equal option_text, autocomplete_option.text
+    assert_equal "", select_element.value
+
+    # when I click on the matching option
+    autocomplete_option.click
+
+    # the autocomplete and select elements reflect my selection
+    assert_equal option_text, autocomplete_input_element.value
+    assert_equal option_value, select_element.value
+  end
+end

test/test_helper.rb

@@ -90,6 +90,7 @@ def assert_not_authorised
 require "support/removing_access_helpers"
 require "support/updating_permissions_helpers"
 require "support/flash_helpers"
+require "support/autocomplete_helpers"
 
 class ActiveRecord::Base
   mattr_accessor :shared_connection
@@ -117,6 +118,7 @@ class ActionDispatch::IntegrationTest
   include RemovingAccessHelpers
   include UpdatingPermissionsHelpers
   include FlashHelpers
+  include AutocompleteHelpers
 
   def assert_response_contains(content)
     assert page.has_content?(content), "Expected to find '#{content}' in:\n#{page.text}"