diff --git a/tests/test_read_buffer/regblock.rdl b/tests/test_read_buffer/regblock.rdl
index 60ffd66..416d985 100644
--- a/tests/test_read_buffer/regblock.rdl
+++ b/tests/test_read_buffer/regblock.rdl
@@ -114,4 +114,13 @@ addrmap top {
     g4_r1->rbuffer_trigger = g4_trig.trig;
     g4_r2->rbuffer_trigger = g4_trig.trig->swmod;
 
+    //--------------------------------------------------------------------------
+    // external components
+    //--------------------------------------------------------------------------
+
+    // ensure read buffering logic is not generated for external components
+    external myreg_wide ext_reg1;
+    external regfile {
+        myreg_wide reg1;
+    } ext_block;
 };
diff --git a/tests/test_write_buffer/regblock.rdl b/tests/test_write_buffer/regblock.rdl
index ca267bc..94c0046 100644
--- a/tests/test_write_buffer/regblock.rdl
+++ b/tests/test_write_buffer/regblock.rdl
@@ -102,5 +102,13 @@ addrmap top {
     } g6_modcount;
     g6_modcount.c->incr = g6_r1.f1->swmod;
 
+    //--------------------------------------------------------------------------
+    // external components
+    //--------------------------------------------------------------------------
 
+    // ensure write buffering logic is not generated for external components
+    external myreg ext_reg1;
+    external regfile {
+        myreg reg1;
+    } ext_block;
 };