Ihor Radchenko <yantar92@posteo.net> writes:

> I saw you using your function to detect the existing duplicate tests.
> However, it would also be nice to add it as a test of its own to detect
> duplicates in future. WDYT?

Sure, here it is. In the patch, I added a new file
(testing/lisp/test-deduplicator.el) with a test that checks for
duplicate forms (not just should, should-not, should-error macros) in
all test files.

Changes in other files serve as an example of how to use
`org-test-ignore-duplicate' to make sure that the test deduplicator
skips certain duplicate forms.

There's a lot of tests to change before merging. I'll handle them and
submit a new patch if you have no questions about the code.