diff --git a/test/DebugProtoTest.thrift b/test/DebugProtoTest.thrift
index 48df1fc..5b2f672 100644
--- a/test/DebugProtoTest.thrift
+++ b/test/DebugProtoTest.thrift
@@ -263,6 +263,11 @@
   5: i32 other_i32_field;
 }
 
+union ComparableUnion {
+  1: string string_field;
+  2: binary binary_field;
+}
+
 struct StructWithAUnion {
   1: TestUnion test_union;
 }