diff --git a/activestorage/test/service/disk_service_test.rb b/activestorage/test/service/disk_service_test.rb
index 4a6361b920..95b535ebc8 100644
--- a/activestorage/test/service/disk_service_test.rb
+++ b/activestorage/test/service/disk_service_test.rb
@@ -11,4 +11,8 @@ class ActiveStorage::Service::DiskServiceTest < ActiveSupport::TestCase
     assert_match(/rails\/active_storage\/disk\/.*\/avatar\.png\?content_type=image%2Fpng&disposition=inline/,
       @service.url(FIXTURE_KEY, expires_in: 5.minutes, disposition: :inline, filename: ActiveStorage::Filename.new("avatar.png"), content_type: "image/png"))
   end
+
+  test "headers_for_direct_upload generation" do
+    assert_equal({ "Content-Type" => "application/json" }, @service.headers_for_direct_upload(FIXTURE_KEY, content_type: "application/json"))
+  end
 end