+ BOOST_REQUIRE_EQUAL (doc.node_children("LoadFont").size(), 1U);
+}
+
+
+static
+void
+check_font_tags (vector<cxml::NodePtr> nodes)
+{
+ for (auto i: nodes) {
+ if (i->name() == "Font") {
+ BOOST_CHECK (!i->optional_string_attribute("Id") || i->string_attribute("Id") != "");
+ }
+ check_font_tags (i->node_children());
+ }
+}
+
+
+/** Check that imported <LoadFont> tags with empty IDs (or corresponding Font tags with empty IDs)
+ * are not passed through into the DCP.
+ */
+BOOST_AUTO_TEST_CASE (dcp_subtitle_test5)
+{
+ auto content = make_shared<DCPSubtitleContent>("test/data/dcp_sub6.xml");
+ auto film = new_test_film2 ("dcp_subtitle_test5", {content});
+ film->set_interop (true);
+
+ make_and_verify_dcp (film, { dcp::VerificationNote::Code::INVALID_STANDARD });
+
+ cxml::Document doc ("DCSubtitle");
+ doc.read_file (subtitle_file(film));
+ BOOST_REQUIRE_EQUAL (doc.node_children("LoadFont").size(), 1U);
+ BOOST_CHECK (doc.node_children("LoadFont").front()->string_attribute("Id") != "");
+
+ check_font_tags (doc.node_children());