1 files changed, 19 insertions, 0 deletions
diff --git a/spec/lib/banzai/filter/image_lazy_load_filter_spec.rb b/spec/lib/banzai/filter/image_lazy_load_filter_spec.rb
new file mode 100644
index 00000000000..c19de7b784a
--- /dev/null
+++ b/spec/lib/banzai/filter/image_lazy_load_filter_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe Banzai::Filter::ImageLazyLoadFilter, lib: true do
+  include FilterSpecHelper
+
+  def image(path)
+    %(<img src="#{path}" />)
+  end
+
+  it 'transforms the image src to a data-src' do
+    doc = filter(image('/uploads/e90decf88d8f96fe9e1389afc2e4a91f/test.jpg'))
+    expect(doc.at_css('img')['data-src']).to eq '/uploads/e90decf88d8f96fe9e1389afc2e4a91f/test.jpg'
+  end
+
+  it 'works with external images' do
+    doc = filter(image('https://i.imgur.com/DfssX9C.jpg'))
+    expect(doc.at_css('img')['data-src']).to eq 'https://i.imgur.com/DfssX9C.jpg'
+  end
+end