test_traceback's PurePythonExceptionFormattingMixin does not fail correctly

[iritkatriel]

class PurePythonExceptionFormattingMixin:
    def get_exception(self, callable, slice_start=0, slice_end=-1):
        try:
            callable()    
            self.fail("No exception thrown.")
        except:
            return traceback.format_exc().splitlines()[slice_start:slice_end]

self.fail simply raises an exception, so putting it in a try..except is not going to work.

Linked PRs

• gh-125514: fix bug in test_traceback utility. Specify exception types in except: clauses #125516
• [3.13] gh-125514: fix bug in test_traceback utility. Specify exception types in except: clauses (GH-125516) #125524
• [3.12] gh-125514: fix bug in test_traceback utility. Specify exception types in except: clauses (GH-125516) #125525