Add test for single letter IDs.

Test: mma

Bug: 32068694
Change-Id: I56659715beaadd8ebb3b9f36558e7ebcdb3e4d27
diff --git a/tests/pointer/1.0/IPointer.hal b/tests/pointer/1.0/IPointer.hal
index e68fb31..4560a4a 100644
--- a/tests/pointer/1.0/IPointer.hal
+++ b/tests/pointer/1.0/IPointer.hal
@@ -17,6 +17,8 @@
 package android.hardware.tests.pointer@1.0;
 
 interface IPointer {
+  struct S { int32_t data; };
+  struct A { S s; };
   // type declarations
   struct Sam { int32_t data; };
   struct Ada { ref<Sam> s_ptr; };