diff --git a/test_regress/t/t_covergroup_cross.py b/test_regress/t/t_covergroup_cross.py
index ceec4c59e..dbc7c1913 100755
--- a/test_regress/t/t_covergroup_cross.py
+++ b/test_regress/t/t_covergroup_cross.py
@@ -11,7 +11,7 @@ import vltest_bootstrap
 
 test.scenarios('vlt_all')
 
-test.compile(verilator_flags2=['--coverage'])
+test.compile(verilator_flags2=['--coverage --dumpi-tree 3 --dumpi-tree-json 3'])
 
 test.execute()
 
diff --git a/test_regress/t/t_covergroup_trans.py b/test_regress/t/t_covergroup_trans.py
index 6e9a8f8a2..662328708 100755
--- a/test_regress/t/t_covergroup_trans.py
+++ b/test_regress/t/t_covergroup_trans.py
@@ -11,7 +11,7 @@ import vltest_bootstrap
 
 test.scenarios('vlt_all')
 
-test.compile(verilator_flags2=['--coverage --Wno-COVERIGN'])
+test.compile(verilator_flags2=['--coverage --Wno-COVERIGN --dumpi-tree 3 --dumpi-tree-json 3'])
 
 test.execute()