diff --git a/scico/test/linop/test_stack.py b/scico/test/linop/test_linop_stack.py
similarity index 100%
rename from scico/test/linop/test_stack.py
rename to scico/test/linop/test_linop_stack.py
diff --git a/scico/test/operator/test_stack.py b/scico/test/operator/test_op_stack.py
similarity index 100%
rename from scico/test/operator/test_stack.py
rename to scico/test/operator/test_op_stack.py