def make_plugin_capitalized_testnames(self, filename: str) -> None:
        """Create a dynamic context plugin that capitalizes the part after 'test_'."""
        self.make_file(filename, """\
            from coverage import CoveragePlugin

            class Plugin(CoveragePlugin):
                def dynamic_context(self, frame):
                    name = frame.f_code.co_name
                    if name.startswith(("test_", "doctest_")):
                        parts = name.split("_", 1)
                        return "%s:%s" % (parts[0], parts[1].upper())
                    return None

            def coverage_init(reg, options):
                reg.add_dynamic_context(Plugin())
            """)
Create a dynamic context plugin that capitalizes the part after 'test_'.
tests/test_plugins.py