You're right — after checking with git grep, it looks like
list_categories() is not currently called anywhere in the
tc-testing framework.

I originally noticed the issue while manually testing the helper
function in a small Python snippet, which triggered the error:

TypeError: unhashable type: 'list'

since the test definitions use a list for category, e.g.:

"category": ["filter", "fw"]

So the patch was intended to make the helper handle that format
correctly. But since the function appears unused today.

Thanks for pointing that out.

On Wed, 4 Mar 2026 at 08:19, Jakub Kicinski [off-list ref] wrote:

On Wed, 4 Mar 2026 08:04:18 +0530 Naveen A wrote:

quoted

quoted

How did you find this issue? I can't figure out what's calling this
function in the first place.

I encountered this while running the tc-testing selftests locally.

Running locally meaning? via tdc.py ? Or some other way ?

$ git grep list_categories
tools/testing/selftests/tc-testing/tdc_helper.py:def list_categories(testlist):

I guess I don't understand what the purpose if tdc_helper.py is
but the function you're polishing appears not to be called today..