Remove 'placeholder' image alt texts

If no image has been selected for news articles, a placeholder image
gets added instead. And when that placeholder image is used,
its alt text reads 'placeholder'.
That is bad for screen reader users as that content doesn't make sense.
It's much better to leave it empty so screen readers can ignore it.

app/models/classification_featuring.rb

@@ -6,7 +6,8 @@ class ClassificationFeaturing < ApplicationRecord
 
   accepts_nested_attributes_for :image, reject_if: :all_blank
 
-  validates :image, :alt_text, presence: true
+  validates :image, presence: true
+  validates :alt_text, presence: true, allow_blank: true
   validates :alt_text, length: { maximum: 255 }
 
   validates :classification, :ordering, presence: true

app/models/feature.rb

@@ -7,7 +7,8 @@ class Feature < ApplicationRecord
   mount_uploader :image, ImageUploader, mount_on: :carrierwave_image
   validates :document, presence: true, unless: ->(feature) { feature.topical_event_id.present? || feature.offsite_link_id.present? }
   validates :started_at, presence: true
-  validates :image, :alt_text, presence: true, on: :create
+  validates :image, presence: true, on: :create
+  validates :alt_text, presence: true, allow_blank: true, on: :create
   validates :alt_text, length: { maximum: 255 }
   validates_with ImageValidator, method: :image, size: [960, 640], if: :image_changed?
 

app/models/image.rb

@@ -2,7 +2,7 @@ class Image < ApplicationRecord
   belongs_to :image_data
   belongs_to :edition
 
-  validates :alt_text, presence: true, length: { maximum: 255 }, unless: :skip_main_validation?
+  validates :alt_text, presence: true, allow_blank: true, length: { maximum: 255 }, unless: :skip_main_validation?
   validates :image_data, presence: { message: 'must be present' }
 
   after_destroy :destroy_image_data_if_required

app/models/take_part_page.rb

@@ -13,7 +13,7 @@ class TakePartPage < ApplicationRecord
   mount_uploader :image, ImageUploader, mount_on: :carrierwave_image
 
   validates :image, presence: true, on: :create
-  validates :image_alt_text, presence: true, length: { maximum: 255 }, on: :create
+  validates :image_alt_text, presence: true, allow_blank: true, length: { maximum: 255 }, on: :create
   validates_with ImageValidator, method: :image, size: [960, 640], if: :image_changed?
 
   include Searchable

app/presenters/lead_image_presenter_helper.rb

@@ -11,7 +11,7 @@ def lead_image_alt_text
     if images.first
       images.first.alt_text.squish
     else
-      'placeholder'
+      ''
     end
   end
 

lib/sync_checker/formats/news_article_check.rb

@@ -72,7 +72,7 @@ def expected_image(news_article)
         image_alt_text = if first_image
                            first_image.alt_text.squish
                          else
-                           'placeholder'
+                           ''
                          end
 
         image_caption = first_image.try(:caption).try(:strip).presence

lib/sync_checker/formats/world_location_news_article_check.rb

@@ -67,7 +67,7 @@ def expected_image(world_location_news_article)
         image_alt_text = if first_image
                            first_image.alt_text.squish
                          else
-                           'placeholder'
+                           ''
                          end
 
         image_caption = first_image.try(:caption).try(:strip).presence

test/unit/lead_image_presenter_helper_test.rb

@@ -4,7 +4,7 @@ class LeadImagePresenterHelperTest < ActiveSupport::TestCase
   test "should use placeholder image if none had been uploaded" do
     presenter = stub("Target", images: [], lead_organisations: [], organisations: []).extend(LeadImagePresenterHelper)
     assert_match %r[placeholder], presenter.lead_image_path
-    assert_equal 'placeholder', presenter.lead_image_alt_text
+    assert_equal '', presenter.lead_image_alt_text
   end
 
   test "should use first image with version :s300 if an image is present" do

test/unit/presenters/publishing_api/case_study_presenter_test.rb

@@ -106,7 +106,7 @@ def present(edition)
 
     expected_hash = {
       url: (Whitehall.public_asset_host + organisation_image.file.url(:s300)),
-      alt_text: 'placeholder',
+      alt_text: '',
       caption: nil
     }
     presented_item = present(case_study)

test/unit/presenters/publishing_api/world_location_news_article_presenter_test.rb

@@ -329,7 +329,7 @@ class PublishingApi::WorldLocationNewsArticlePlaceholderImageTest < ActiveSuppor
 
   test "includes a placeholder image when no image is presented" do
     expected_placeholder_image = {
-      alt_text: "placeholder",
+      alt_text: "",
       caption: nil,
       url: Whitehall.public_asset_host + "/government/assets/placeholder.jpg"
     }