Filter for tests that are uncategorized

[Youssef1313]

Discussed in #5134

^{Originally posted by mscottford February 25, 2025}
I'd like the ability to generate a list of tests that don't have a category specified. My use case is that I'm trying to monitor the number of tests in my test suite that have not been categorized so that I can ensure the number continues to go down over time as the team adds categories to tests.

I found microsoft/vstest#2818 which concluded with a note that such a feature wouldn't be implemented in vstest, so I thought I'd bring up the idea here.

I took a peek at the source for --treenode-filter to get a sense about whether or not it would work. The only thing that isn't clear to me from reading through it is how categories would be represented for tests that haven't had a category defined. Would that be an empty string? And then I could write an expression that searches for tests with a 0 length category? Perhaps with ^$.