Check rval with assertEqual

src/lager_crash_log.erl

@@ -303,8 +303,8 @@ filesystem_test_() ->
                 sync_error_logger:error_msg("Test message\n"),
                 _ = gen_event:which_handlers(error_logger),
                 ?assertEqual(1, lager_test_backend:count()),
-                file:delete(CrashLog),
-                ok = lager_util:safe_write_file(CrashLog, ""),
+                ?assertEqual(ok, file:delete(CrashLog)),
+                ?assertEqual(ok, lager_util:safe_write_file(CrashLog, "")),
                 {ok, FInfo0} = file:read_file_info(CrashLog, [raw]),
                 FInfo1 = FInfo0#file_info{mode = 0},
                 ?assertEqual(ok, file:write_file_info(CrashLog, FInfo1)),