+1 to TP's proposal too.
It's easy to read and also stands out better.
We have a few places in the task-sdk tests where we also have done patterns
like:
assert not any(
x
== mock.call(
msg=GetXCom(
key="key",
dag_id="test_dag",
run_id="test_run",
task_id="pull_task",
map_index=-1,
),
)
for x in mock_supervisor_comms.send.call_args_list
)
call_args_list is particularly useful in scenarios when you want to
validate presence / absence of a call.
Thanks & Regards,
Amogh Desai
On Thu, Jul 10, 2025 at 8:39 PM Kyungjun Lee <kyungjunlee...@gmail.com>
wrote:
> Thank you all — I really appreciate how many people have joined the
> discussion.
>
> I also like the approach that Tzu-ping Chung suggested. This really isn’t
> an easy topic. At first, I thought it would be best to use only plain
> assert
> statements, but after reading through the different perspectives here, I’ve
> come to realize that overusing assert can also be problematic. It’s been a
> great reminder that we should be intentional about what we choose to assert
> — making sure we’re testing what truly matters.
>
>
> I’ll also follow up soon with an example snippet and a brief testing guide
> to help clarify the discussion.
>
> 2025년 7월 10일 (목) 오후 11:49, Tzu-ping Chung <t...@astronomer.io.invalid>님이 작성:
>
> > Does pytest-mock have an equivalent for call()? I agree for mocking in
> > general we should consider replacing plain decorators and context
> managers
> > with the mocker fixture. This probably deserves its own discussion
> thread.
> >
> > --
> > Sent from my iPhone
> >
> > > On 10 Jul 2025, at 14:37, Dev-iL <gid....@gmail.com> wrote:
> > >
> > > One tiny comment regarding TP's suggestion - IMHO it's better to avoid
> > `unittest.mock` in favor of the equivalent `mocker` fixture provided by
> > `pytest-mock`.
> > >
> > > On 2025/07/10 06:30:22 Tzu-ping Chung wrote:
> > > > Personally I dislike things like assert_called_once_with etc. since
> > they are easy to miss when you scan a test to see what they are trying to
> > check. An 'assert' keyword stands out (it’s always the first word in the
> > line), especially with syntax highlighting.
> > > >
> > > > I do agree the proposed Pytest style is arguably less readable. I
> > offer another syntax.
> > > >
> > > >
> > > > from unittest.mock import call
> > > >
> > > > assert mock_http_run.mock_calls == [
> > > > call(
> > > > endpoint=f"api/v2/accounts/{expected_account_id}/",
> > > > data=None,
> > > > extra_options=None,
> > > > )
> > > > ]
> > > > assert mock_paginate.mock_calls == []
> > > >
> > > >
> > > > To me, this is on par with assert_called_once_with et al. in terms of
> > readability, and arguably better for test authors since you don’t need to
> > remember the various function names anymore, but only 'mock_calls' and
> the
> > 'call' helper class.
> > > >
> > > > TP
> > > >
> > > >
> > > > > On Jul 9, 2025, at 23:28, Ferruzzi, Dennis
> <fe...@amazon.com.INVALID>
> > wrote:
> > > > >
> > > > > I'm a bit late to the party, and really only reiterating what has
> > already been said, but of the two examples (original and your rewrite, I
> > prefer the original. I think as a general rule, we tend to use the
> > assert_called_once, etc with mocks butt he asserts with non-mocked
> > variables.
> > > > >
> > > > > I am all for more documentation, but I'd have a slight preference
> > towards keeping the existing structure.
> > > > >
> > > > >
> > > > > - ferruzzi
> > > > >
> > > > >
> > > > > ________________________________
> > > > > From: Kyungjun Lee <ky...@gmail.com>
> > > > > Sent: Tuesday, July 8, 2025 2:13 AM
> > > > > To: dev@airflow.apache.org
> > > > > Subject: RE: [EXT] [DISCUSS] Consistent test assertion style:
> > pytest-native vs unittest-style
> > > > >
> > > > > CAUTION: This email originated from outside of the organization. Do
> > not click links or open attachments unless you can confirm the sender and
> > know the content is safe.
> > > > >
> > > > >
> > > > >
> > > > > AVERTISSEMENT: Ce courrier électronique provient d’un expéditeur
> > externe. Ne cliquez sur aucun lien et n’ouvrez aucune pièce jointe si
> vous
> > ne pouvez pas confirmer l’identité de l’expéditeur et si vous n’êtes pas
> > certain que le contenu ne présente aucun risque.
> > > > >
> > > > >
> > > > >
> > > > > Thank you Ash and Amogh Desai for your insights and explanations.
> > > > > The information you shared has been incredibly helpful and is
> > contributing
> > > > > a lot to my growth.
> > > > >
> > > > > 2025년 7월 8일 (화) 오후 2:54, Amogh Desai <am...@gmail.com>님이 작성:
> > > > >
> > > > >> Agreed, I personally also find the current way to be easier to
> read
> > and in
> > > > >> most
> > > > >> cases we want to assert if "something" was called, irrespective of
> > the
> > > > >> order it was
> > > > >> called in. So the dedicated function based way works well for me.
> > > > >>
> > > > >> If I want to test a order, I'd rather call parts of code that I
> > want to
> > > > >> test explicitly and assert
> > > > >> on them.
> > > > >>
> > > > >>> This happens because the mock object is not properly recognized
> as
> > a mock
> > > > >> instance at type-checking time, which might confuse some
> > contributors,
> > > > >> especially new ones relying on type hints or static analysis
> tools.
> > > > >>
> > > > >> Regarding this, I'd say you can either cast mocks to their types
> as
> > one
> > > > >> way:
> > > > >> `mock_http_run: MagicMock = mock_http_run` -- give or take, or use
> > > > >> `autospec` to make the mock reflect the signature of the object?
> > Check out:
> > > > >> https://docs.python.org/3/library/unittest.mock.html#autospeccing
> > > > >>
> > > > >> Thanks & Regards,
> > > > >> Amogh Desai
> > > > >>
> > > > >>
> > > > >> On Mon, Jul 7, 2025 at 6:13 PM Ash Berlin-Taylor <
> as...@apache.org>
> > wrote:
> > > > >>
> > > > >>> def test_get_account(self, mock_paginate: Mock, mock_http_run:
> > Mocj,
> > > > >>> conn_id, account_id):
> > > > >>>
> > > > >>>
> > > > >>> Might fix that? IDEs in general do not cope well with purest
> > tests, and
> > > > >>> are missing context on what most of the variables are, be it
> > > > >> parameterised
> > > > >>> values or fixture values, so this isn’t a problem that is unique
> to
> > > > >> mocks.
> > > > >>>
> > > > >>>> On 7 Jul 2025, at 12:47, Kyungjun Lee <ky...@gmail.com>
> > > > >> wrote:
> > > > >>>>
> > > > >>>> I'd like to follow up on our previous discussion about
> > pytest-native vs
> > > > >>>> unittest-style assertions.
> > > > >>>>
> > > > >>>> While working on the following test case:
> > > > >>>>
> > > > >>>> ```python
> > > > >>>>
> > > > >>>> @pytest.mark.parametrize(
> > > > >>>> argnames="conn_id, account_id",
> > > > >>>> argvalues=[(ACCOUNT_ID_CONN, None), (NO_ACCOUNT_ID_CONN,
> > > > >> ACCOUNT_ID)],
> > > > >>>> ids=["default_account", "explicit_account"],
> > > > >>>> )
> > > > >>>> @patch.object(DbtCloudHook, "run")
> > > > >>>> @patch.object(DbtCloudHook, "_paginate")
> > > > >>>> def test_get_account(self, mock_paginate, mock_http_run,
> conn_id,
> > > > >>>> account_id):
> > > > >>>> hook = DbtCloudHook(conn_id)
> > > > >>>> hook.get_account(account_id=account_id)
> > > > >>>>
> > > > >>>> assert hook.method == "GET"
> > > > >>>>
> > > > >>>> _account_id = account_id or DEFAULT_ACCOUNT_ID
> > > > >>>> hook.run.assert_called_once_with(
> > > > >>>> endpoint=f"api/v2/accounts/{_account_id}/", data=None,
> > > > >>>> extra_options=None
> > > > >>>> )
> > > > >>>> hook._paginate.assert_not_called()
> > > > >>>>
> > > > >>>> ```
> > > > >>>>
> > > > >>>> My IDE shows a warning:
> > > > >>>> Cannot find reference 'assert_called_once_with' in 'function'.
> > > > >>>>
> > > > >>>> This happens because the mock object is not properly recognized
> > as a
> > > > >> mock
> > > > >>>> instance at type-checking time, which might confuse some
> > contributors,
> > > > >>>> especially new ones relying on type hints or static analysis
> > tools.
> > > > >>>>
> > > > >>>> I realized that this aspect of mock handling might be missing
> > from our
> > > > >>>> previous discussions. I wanted to bring it up as part of the
> > broader
> > > > >>>> conversation about test styles—particularly how we balance
> > IDE/tooling
> > > > >>>> support with readability and style consistency.
> > > > >>>>
> > > > >>>> Curious to hear your thoughts on this!
> > > > >>>>
> > > > >>>> @ash @potiuk
> > > > >>>>
> > > > >>>> 2025년 7월 6일 (일) 오후 8:09, Kyungjun Lee <ky...@gmail.com>님이 작성:
> > > > >>>>
> > > > >>>>> Thank you @Potiuk for pointing out the intent behind the “one
> > assert
> > > > >> per
> > > > >>>>> test” principle, and @ash for highlighting how using dedicated
> > mock
> > > > >>> assert
> > > > >>>>> functions can make the code easier to read and understand.
> These
> > were
> > > > >>>>> perspectives I hadn’t fully considered, and I really appreciate
> > you
> > > > >>> sharing
> > > > >>>>> them.
> > > > >>>>>
> > > > >>>>> Thanks to your input, I was able to read more materials and
> > broaden my
> > > > >>>>> thinking on the topic. That said, my original focus was more on
> > the
> > > > >> idea
> > > > >>>>> that sticking to plain assert statements lowers the entry
> > barrier for
> > > > >>> new
> > > > >>>>> contributors—because they don’t have to learn multiple
> assertion
> > > > >> styles.
> > > > >>>>>
> > > > >>>>> Still, as @Potiuk mentioned, I’ll put more thought into making
> > the
> > > > >>> testing
> > > > >>>>> guidelines clearer and more concrete—especially since that
> helps
> > > > >>> AI-based
> > > > >>>>> tools as well 😄
> > > > >>>>>
> > > > >>>>> For reference, here’s one of the articles I read:
> > > > >>>>> https://medium.com/@kentbeck_7670/test-desiderata-94150638a4b3
> > > > >>>>>
> > > > >>>>> Thank you to everyone who took part in this discussion.
> > > > >>>>>
> > > > >>>>> 2025년 7월 6일 (일) 오후 3:42, Ash Berlin-Taylor <as...@apache.org
> >님이
> > 작성:
> > > > >>>>>
> > > > >>>>>> I personally find the dedicated functions way easier to read
> the
> > > > >> intent
> > > > >>>>>> behind, it’s one function/statement vs 3. More so when you
> > don’t care
> > > > >>> about
> > > > >>>>>> the order of calls, just that something was called (where to
> do
> > this
> > > > >>>>>> manually we’d need to reimplement the helper function)
> > > > >>>>>>
> > > > >>>>>> Additionally pytest already rewrites those to have nicer error
> > > > >>> messages,
> > > > >>>>>> but the dedicated mock assert finding are much easier to read
> > the
> > > > >> code
> > > > >>> and
> > > > >>>>>> understand the intent to me, so I’i am for staying with the
> > dedicated
> > > > >>>>>> assert functions
> > > > >>>>>>
> > > > >>>>>> -ash
> > > > >>>>>>
> > > > >>>>>>> On 5 Jul 2025, at 13:30, Kyungjun Lee <ky...@gmail.com>
> > > > >>> wrote:
> > > > >>>>>>>
> > > > >>>>>>> I’ve learned a lot of things I didn’t know before.
> > > > >>>>>>> Thank you so much for all your help — I really appreciate it.
> > > > >>>>>>> I’ll get started on this right away!
> > > > >>>>>>>
> > > > >>>>>>> 2025년 7월 5일 (토) 오후 9:18, Jarek Potiuk <ja...@potiuk.com>님이
> 작성:
> > > > >>>>>>>
> > > > >>>>>>>>> Haha ... I'm curious — which part sounded like ChatGPT
> style?
> > > > >>>>>>>> English isn't my first language, so I did get a little help
> > from
> > > > >> it.
> > > > >>>>>>>>
> > > > >>>>>>>> That whole paragraph :) .
> > > > >>>>>>>>
> > > > >>>>>>>>>> Sure! Since you asked for how the test *should* be
> written,
> > I
> > > > >> took
> > > > >>>>>> the
> > > > >>>>>>>> opportunity to clean it up using a more pytest-native style
> > while
> > > > >>> also
> > > > >>>>>>>> fixing the mock order issue.
> > > > >>>>>>>>
> > > > >>>>>>>> "Sure! Since you asked ..." sounds like an AI bot.
> > > > >>>>>>>>
> > > > >>>>>>>>> That got me thinking — what do you think about adding a
> > guideline
> > > > >>>>>>>> document
> > > > >>>>>>>> for writing tests, similar to how we have a coding style
> > guide?
> > > > >>>>>>>>
> > > > >>>>>>>> Absolutely - we already have some "seed' of it "Writing
> tests"
> > > > >>>>>> chapter in
> > > > >>>>>>>> contributing guideline, but we could definitely make it more
> > > > >>> detailed.
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>
> > > > >>>
> > > > >>
> >
> https://github.com/apache/airflow/blob/main/contributing-docs/testing/unit_tests.rst#writing-unit-tests
> > > > >>>>>>>>
> > > > >>>>>>>> And - speaking of AI - this is becoming more and more
> > important to
> > > > >>>>>> describe
> > > > >>>>>>>> any common rules we have and context - so that using Agentic
> > AI
> > > > >>> yields
> > > > >>>>>>>> better results. Kaxil already added
> > > > >>>>>>>> https://github.com/apache/airflow/blob/main/AGENTS.md which
> > > > >>> describes
> > > > >>>>>>>> context for coding agents lile Codex - and we could improve
> > it and
> > > > >>> link
> > > > >>>>>>>> more docs from our repo if they get more of our agreed
> > > > >> "conventions"
> > > > >>> -
> > > > >>>>>> then
> > > > >>>>>>>> Agents would get it as context and their generated code
> would
> > be
> > > > >>>>>> consistent
> > > > >>>>>>>> with what we describe there.
> > > > >>>>>>>>
> > > > >>>>>>>> In a way - I think having a good documentation on processes,
> > tools
> > > > >>> and
> > > > >>>>>>>> conventions was always something I've been after, but with
> the
> > > > >>> Agentic
> > > > >>>>>>>> workflows it might significantly boost the quality of
> > generated
> > > > >> code
> > > > >>>>>> if we
> > > > >>>>>>>> have more of those conventions and guidelines described.
> > > > >>>>>>>>
> > > > >>>>>>>> So .... ABSOLUTELY ... the more we describe in there, the
> > better.
> > > > >> And
> > > > >>>>>> we
> > > > >>>>>>>> have no more excuse that "anyhow no-one reads it" - because
> > the
> > > > >>> coding
> > > > >>>>>>>> agents WILL be reading it and acting accordingly. So I think
> > this
> > > > >> is
> > > > >>> a
> > > > >>>>>> very
> > > > >>>>>>>> good investment to make.
> > > > >>>>>>>>
> > > > >>>>>>>> J.
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>>
> > > > >>>>>>>>> On Sat, Jul 5, 2025 at 2:07 PM Kyungjun Lee <
> > > > >>> kyungjunlee...@gmail.com
> > > > >>>>>>>
> > > > >>>>>>>>> wrote:
> > > > >>>>>>>>>
> > > > >>>>>>>>> Haha ... I'm curious — which part sounded like ChatGPT
> style?
> > > > >>>>>>>>> English isn't my first language, so I did get a little help
> > from
> > > > >> it.
> > > > >>>>>>>>>
> > > > >>>>>>>>> But thank you — I actually learned something new from your
> > > > >> comment!
> > > > >>>>>>>>> That got me thinking — what do you think about adding a
> > guideline
> > > > >>>>>>>> document
> > > > >>>>>>>>> for writing tests, similar to how we have a coding style
> > guide? It
> > > > >>>>>> might
> > > > >>>>>>>>> help ensure consistency across the Airflow codebase when it
> > comes
> > > > >> to
> > > > >>>>>>>>> testing styles as well.
> > > > >>>>>>>>>
> > > > >>>>>>>>> 2025년 7월 5일 (토) 오후 8:52, Jarek Potiuk <ja...@potiuk.com>님이
> > 작성:
> > > > >>>>>>>>>
> > > > >>>>>>>>>> But of course - i'd love to hear what others think - it's
> > not a
> > > > >>> "very
> > > > >>>>>>>>>> strong" opinion.
> > > > >>>>>>>>>>
> > > > >>>>>>>>>> On Sat, Jul 5, 2025 at 1:48 PM Jarek Potiuk <
> > ja...@potiuk.com>
> > > > >>>>>> wrote:
> > > > >>>>>>>>>>
> > > > >>>>>>>>>>> Cool. That's what I wanted to see.
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> By the way - not that there's anything wrong - but was
> the
> > > > >> answer
> > > > >>>>>>>>> written
> > > > >>>>>>>>>>> by AI initially ? The first paragraph looks suspiciously
> > like
> > > > >> Chat
> > > > >>>>>>>> GPT
> > > > >>>>>>>>>>> answer :D ?
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> Comment from my side: I personally prefer the original
> > style.
> > > > >> It's
> > > > >>>>>>>> more
> > > > >>>>>>>>>>> concise and it is easier to read - you see as if the call
> > was
> > > > >>>>>>>> actually
> > > > >>>>>>>>>>> written down. Also this is quite a bit too many
> assertions
> > in
> > > > >> the
> > > > >>>>>>>>> second
> > > > >>>>>>>>>>> case and it takes a lot of mental effort to understand
> what
> > > > >>> actually
> > > > >>>>>>>> is
> > > > >>>>>>>>>>> being asserted.
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> There is a "school" of writing unit tests that every test
> > should
> > > > >>>>>> have
> > > > >>>>>>>>> ONE
> > > > >>>>>>>>>>> assertion only. Always. I think it is a bit extreme, and
> I
> > do
> > > > >> not
> > > > >>>>>>>>> follow
> > > > >>>>>>>>>> it
> > > > >>>>>>>>>>> myself but I think it is also a kind of good direction to
> > have
> > > > >> ->
> > > > >>>>>> the
> > > > >>>>>>>>>> fewer
> > > > >>>>>>>>>>> assertions you have in your test, the better (I think).
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> I think tests should be mostly optimized for easiness of
> > reading
> > > > >>> and
> > > > >>>>>>>>>>> understanding what is being tested - and it's just not
> > that easy
> > > > >>> in
> > > > >>>>>>>> the
> > > > >>>>>>>>>>> second case.
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> J.
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>> On Sat, Jul 5, 2025 at 1:39 PM Kyungjun Lee <
> > > > >>>>>>>> kyungjunlee...@gmail.com>
> > > > >>>>>>>>>>> wrote:
> > > > >>>>>>>>>>>
> > > > >>>>>>>>>>>> Sure! Since you asked for how the test *should* be
> > written, I
> > > > >>> took
> > > > >>>>>>>> the
> > > > >>>>>>>>>>>> opportunity to clean it up using a more pytest-native
> > style
> > > > >> while
> > > > >>>>>>>> also
> > > > >>>>>>>>>>>> fixing the mock order issue.
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> Here’s the updated test:
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> ```python
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> @pytest.mark.parametrize(
> > > > >>>>>>>>>>>> argnames="conn_id, account_id",
> > > > >>>>>>>>>>>> argvalues=[(ACCOUNT_ID_CONN, None), (NO_ACCOUNT_ID_CONN,
> > > > >>>>>>>>>> ACCOUNT_ID)],
> > > > >>>>>>>>>>>> ids=["default_account", "explicit_account"],
> > > > >>>>>>>>>>>> )
> > > > >>>>>>>>>>>> @patch.object(DbtCloudHook, "run")
> > > > >>>>>>>>>>>> @patch.object(DbtCloudHook, "_paginate")
> > > > >>>>>>>>>>>> def test_get_account(self, mock_paginate, mock_http_run,
> > > > >> conn_id,
> > > > >>>>>>>>>>>> account_id):
> > > > >>>>>>>>>>>> hook = DbtCloudHook(conn_id)
> > > > >>>>>>>>>>>> hook.get_account(account_id=account_id)
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> assert hook.method == "GET"
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> expected_account_id = account_id or DEFAULT_ACCOUNT_ID
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> assert mock_http_run.call_count == 1
> > > > >>>>>>>>>>>> assert mock_http_run.call_args.args == ()
> > > > >>>>>>>>>>>> assert mock_http_run.call_args.kwargs == {
> > > > >>>>>>>>>>>> "endpoint": f"api/v2/accounts/{expected_account_id}/",
> > > > >>>>>>>>>>>> "data": None,
> > > > >>>>>>>>>>>> "extra_options": None,
> > > > >>>>>>>>>>>> }
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> assert mock_paginate.call_count == 0
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> ```
> > > > >>>>>>>>>>>> Why I chose this style:
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> -
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> *Mock verification using assert*: Instead of
> > > > >>>>>>>>>>>> mock.assert_called_once_with(...), I used call_count and
> > > > >>>>>>>> call_args.
> > > > >>>>>>>>>>>> This
> > > > >>>>>>>>>>>> approach aligns better with pytest’s idioms and produces
> > > > >>> cleaner,
> > > > >>>>>>>>>> more
> > > > >>>>>>>>>>>> readable error messages when assertions fail.
> > > > >>>>>>>>>>>> -
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> *Explicit verification*: Using call_args.args and
> > > > >>>>>>>> call_args.kwargs
> > > > >>>>>>>>>>>> makes
> > > > >>>>>>>>>>>> the test behavior very explicit, which helps with
> > debugging
> > > > >> and
> > > > >>>>>>>>>>>> understanding the exact calls made.
> > > > >>>>>>>>>>>> -
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> *Decorator order matching argument order*: As @patch
> > > > >> decorators
> > > > >>>>>>>>> apply
> > > > >>>>>>>>>>>> from the bottom up, the argument order has been
> corrected
> > to
> > > > >>>>>>>> match
> > > > >>>>>>>>> (
> > > > >>>>>>>>>>>> mock_paginate first, then mock_http_run).
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> Let me know if you'd like to follow a slightly different
> > > > >>> convention
> > > > >>>>>>>> —
> > > > >>>>>>>>>>>> happy
> > > > >>>>>>>>>>>> to adjust!
> > > > >>>>>>>>>>>>
> > > > >>>>>>>>>>>> I was lu
> > > [message truncated...]
> >
> > ---------------------------------------------------------------------
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> > For additional commands, e-mail: dev-h...@airflow.apache.org
> >
> >
>
