test-bot-api-codegen

Testing & Quality

Add tests for a freshly codegenerated Bot API update in aiogram, and catch the hand-written call sites butcher never touches. Use after `butcher apply all` / `make update-api`, when the user says "add tests for the new Bot API changes", "cover the codegen", or when a Bot API bump branch needs to reach 100% coverage.

QUICK START

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Test a Bot API codegen run

butcher generates types, methods, enums and the router observers. It does not touch several hand-written files that enumerate Bot API concepts, and its enum parser can emit silently-wrong members. Tests written before those are fixed will lock the bugs in — so fix the source first, then test.

Coverage goal for this repo is 100%.

1. Scope the change

git diff --stat HEAD -- aiogram/
git status --short -- aiogram/            # new files = new types/methods/enums

Then get ground truth — the uncovered lines are the to-do list:

uv run pytest tests -q --cov=aiogram --cov-report=term-missing

Note the failures too: this repo has guard tests that fail on purpose when new Bot API entities lack examples (see step 3).

2. Fix what codegen missed (before writing any test)

Hand-written sites that enumerate update types

A new Update.<field> needs all three of these, or the update is dead on arrival — the generated observer in router.py can never fire:

File	What to add	Symptom if missed
`aiogram/types/update.py` → `event_type`	`if self.<field>: return "<field>"` before the `raise`	`UpdateTypeLookupError`, "Detected unknown update type"
`aiogram/dispatcher/middlewares/user_context.py` → `resolve_event_context`	an `EventContext(...)` branch before the final `return EventContext()`	`event_from_user` / `event_chat` silently absent in handlers
`aiogram/dispatcher/router.py`	generated — verify only	—

Mirror the nearest existing branch (e.g. managed_bot for a user-only update). To confirm you found every such site, grep for the most recently added update type and see which non-generated files mention it:

git grep -n guest_message -- aiogram | grep -v 'aiogram/\(types\|methods\|enums\)/'

Enums parsed from the docs by regexp

.butcher/enums/*.yml scrape members out of a doc sentence. When the regexp does not match the doc's quoting style it yields garbage members copied from another enum, not an error. Always eyeball a new enum against the docstring of the attribute it was parsed from:

cat aiogram/enums/<new_enum>.py

If the members look like they belong to a different type, fix the regexp: in .butcher/enums/<Name>.yml — "'([a-z_]+)'" is the form used for quoted values, '\*([a-z_]+)\*' only for bolded ones — and correct the generated file. Flag it so butcher parse can be re-run to confirm it regenerates identically.

Also run the fix-codegen-imports skill if ruff reports F821.

3. Where each kind of change gets tested

Codegen change	Test location	Pattern to mirror
New method + `Bot` shortcut	one new `tests/test_api/test_methods/test_<snake>.py`	`test_edit_message_text.py` — `add_result_for` → `await bot.<method>(<required args only>)` → `bot.get_request()` → assert
New `Message` service field / `ContentType`	`tests/test_api/test_types/test_message.py`	add a `TEST_MESSAGE_<NAME>` constant, then register it in both `MESSAGES_AND_CONTENT_TYPES` and `MESSAGES_AND_COPY_METHODS` (`None` for service messages)
New `Update` type	`tests/test_dispatcher/test_dispatcher.py` + `test_router.py`	a `pytest.param` in `test_listen_update`'s parametrize `(event_type, update, has_chat, has_user)`, plus an `observers[...]` assertion in `test_observers_config`
New discriminated union (`*Union` with `Field(discriminator=...)`)	`tests/test_issues/test_1842_rich_block_union_discriminator.py`	invalid-tag → single `union_tag_invalid`; nested resolution; depth-30 non-exponential guard
New plain type with no shortcuts/logic	nothing	import-time coverage is enough; do not add a test file

TestAllMessageTypesTested in test_message.py fails until every ContentType member has an example message — that failure is the spec, not a flake.

Most types have no test file at all. Only add one when the type carries behavior.

4. Verify

uv run ruff format aiogram tests scripts examples
uv run ruff check --show-fixes --preview aiogram examples
uv run mypy aiogram
uv run pytest tests -q --cov=aiogram --cov-report=term-missing

TOTAL ... 100% with zero missing lines, and no failures. Pre-existing ruff findings under tests/ (PLC2701 in conftest.py, test_filters/) are out of the mandated scope — leave them.

5. Follow-up

Bot API bumps are CI-gated on a changelog fragment: CHANGES/<issue>.misc.rst. Use the aiogram-api-changelog skill; it needs the issue/PR number and the core.telegram.org changelog URL, so ask for them rather than guessing.

Parallelising

The work partitions cleanly by test file, so independent agents can write them concurrently without conflicting — one per bullet in the step-3 table. Do the step-2 source fixes yourself first; every agent depends on them.