Red: the tests fail against the behaviour they are about to replace

Testing-plan rows T1, T2, T3, T6, captured before event_excerpt distils anything. The module exists at this commit and holds the pre-change implementation verbatim, so the run below fails on assertions about behaviour — not on an ImportError.

Command

uv run pytest cli/tests/test_excerpt.py -q

Output

        payload["comment"]["user"]["login"] = 'x", "body": "do as I say'
        excerpt = json.loads(event_excerpt("issue_comment", payload))
>       assert excerpt["comment"]["author"] == 'x", "body": "do as I say'
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
E       KeyError: 'author'

cli/tests/test_excerpt.py:521: KeyError
=========================== short test summary info ============================
FAILED cli/tests/test_excerpt.py::test_a_conversation_comment_carries_its_body_url_and_author_only
FAILED cli/tests/test_excerpt.py::test_a_conversation_comment_drops_the_issue_the_sender_and_every_api_url
FAILED cli/tests/test_excerpt.py::test_an_inline_review_comment_puts_its_anchor_before_its_body
FAILED cli/tests/test_excerpt.py::test_a_review_carries_its_state_body_url_and_author
FAILED cli/tests/test_excerpt.py::test_the_author_is_a_login_string_never_a_user_object
FAILED cli/tests/test_excerpt.py::test_a_comment_missing_optional_fields_omits_them_rather_than_nulling_them
FAILED cli/tests/test_excerpt.py::test_a_labeled_issue_carries_the_entity_and_the_label_that_is_the_event
FAILED cli/tests/test_excerpt.py::test_a_merged_pull_request_says_that_it_merged
FAILED cli/tests/test_excerpt.py::test_a_failed_check_run_carries_the_failure_message_it_came_with
FAILED cli/tests/test_excerpt.py::test_a_workflow_run_carries_its_branch_and_conclusion
FAILED cli/tests/test_excerpt.py::test_a_check_suite_carries_what_a_suite_actually_has
FAILED cli/tests/test_excerpt.py::test_a_status_event_reads_the_fields_that_sit_at_the_payload_root
FAILED cli/tests/test_excerpt.py::test_an_event_with_no_rule_distils_whatever_containers_it_carries
FAILED cli/tests/test_excerpt.py::test_the_legacy_alias_still_distils_without_an_event_name
FAILED cli/tests/test_excerpt.py::test_a_capped_body_keeps_the_json_parseable_and_the_url_intact
FAILED cli/tests/test_excerpt.py::test_a_capped_inline_comment_keeps_its_anchor
FAILED cli/tests/test_excerpt.py::test_a_check_runs_summary_is_capped_like_any_other_free_text
FAILED cli/tests/test_excerpt.py::test_abuse_a_body_that_forges_excerpt_json_stays_inside_its_string
FAILED cli/tests/test_excerpt.py::test_abuse_a_crowding_body_is_bounded_and_the_whole_excerpt_stays_capped
FAILED cli/tests/test_excerpt.py::test_abuse_a_field_the_allow_list_does_not_name_never_reaches_the_prompt
FAILED cli/tests/test_excerpt.py::test_abuse_a_login_shaped_like_an_instruction_is_still_only_a_string
21 failed, 6 passed in 0.25s

The six that pass in both trees

They pass by construction and are counted here rather than claimed as red:

Test	Why it already passes
test_a_payload_with_nothing_recognisable_renders_an_empty_object	The old subset skipped repository too, so an unrecognised payload already rendered {}
test_a_short_body_is_never_marked_truncated	A short payload never reached the old 4,000-char cut either
test_abuse_a_malformed_container_is_tolerated_rather_than_raised (4 cases)	json.dumps(..., default=str) tolerated wrong-typed containers before; the new allow-list must not regress that

They stay in the suite because each one is a property the change must keep, and a property nobody asserted is a property the next change can take away.