tests: Improve test coverage

tests/test_document.cpp

@@ -301,6 +301,10 @@ TEST(document_load_file_error)
 
 	CHECK(doc.load_file("filedoesnotexist").status == status_file_not_found);
 
+#ifndef _WIN32
+	CHECK(doc.load_file("/dev/tty").status == status_io_error);
+#endif
+
 	test_runner::_memory_fail_threshold = 1;
 	CHECK(doc.load_file("tests/data/small.xml").status == status_out_of_memory);
 }

tests/test_xpath_paths.cpp

@@ -664,6 +664,8 @@ TEST_XML(xpath_paths_optimize_step_once, "<node><para1><para2/><para3/><para4><p
 
     CHECK_XPATH_BOOLEAN(doc, STR("//para5/ancestor-or-self::*"), true);
     CHECK_XPATH_BOOLEAN(doc, STR("//para5/ancestor::*"), true);
+
+    CHECK_XPATH_BOOLEAN(doc, STR("//@attr5/ancestor-or-self::node()"), true);
 }
 
 TEST_XML(xpath_paths_null_nodeset_entries, "<node attr='value'/>")