From: Han-Wen Nienhuys <hanwen@google.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Patrick Steinhardt <ps@pks.im>, git@vger.kernel.org
Subject: Re: [PATCH 00/11] t: reduce direct disk access to data structures
Date: Thu, 19 Oct 2023 12:13:12 +0200 [thread overview]
Message-ID: <CAFQ2z_Om724+o+EG1FAhC9VrvJECnQ5UA+Z04Rzycpi_mXvMHg@mail.gmail.com> (raw)
In-Reply-To: <xmqqbkcwuetq.fsf@gitster.g>
On Wed, Oct 18, 2023 at 5:32 PM Junio C Hamano <gitster@pobox.com> wrote:
> > this patch series refactors a bunch of our tests to perform less direct
> > disk access to on-disk data structures. Instead, the tests are converted
> > to use Git tools or our test-tool to access data to the best extent
> > possible. This serves two benefits:
>
> Laudable goal.
>
> > - We increase test coverage of our own code base.
>
> Meaning the new code added to test-tool for this series will also
> get tested and bugs spotted?
>
> > - We become less dependent on the actual on-disk format.
>
> Yes, this is very desirable. Without looking at the implementation,
> I see some issues aiming for this goal may involve. [a] using the
> production code for validation would mean our expectation to be
> compared to the reality to be validated can be affected by the same
> bug, making two wrongs to appear right; [b] using a separate
> implementation used only for validation would at least mean we will
> have to make the same mistake in unique part of both implementations
> that is less likely to miss bugs compared to [a], but bugs in shared
> part of the production code and validation code will be hidden the
> same way as [a].
I think it would be really great if there were separate unittests for
the ref backend API. Some of the reftable work was needlessly
difficult because the contract of the API was underspecified. The API
is well compartmentalized in refs-internal.h, and a lot of the API
behavior can be tested as a black box, eg.
* setup symref HEAD pointing to R1
* setup transaction updating ref R1 from C1 to C2
* commit transaction, check that it succeeds
* read ref R1, check if it is C2
* read reflog for R1, see that it has a C1 => C2 update
* read reflog for HEAD, see that it has a C1 => C2 update
Tests for the loose/packed backend could directly mess with the
on-disk files to test failure scenarios.
With unittests like that, the tests can zoom in on the functionality
of the ref backend, and provide more convenient coverage for
dynamic/static analysis.
--
Han-Wen Nienhuys - Google Munich
I work 80%. Don't expect answers from me on Fridays.
--
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next prev parent reply other threads:[~2023-10-19 10:13 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-18 5:35 [PATCH 00/11] t: reduce direct disk access to data structures Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 01/11] t: add helpers to test for reference existence Patrick Steinhardt
2023-10-18 16:06 ` Junio C Hamano
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-18 17:08 ` Eric Sunshine
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 02/11] t: allow skipping expected object ID in `ref-store update-ref` Patrick Steinhardt
2023-10-18 16:08 ` Junio C Hamano
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-23 19:06 ` Junio C Hamano
2023-10-18 5:35 ` [PATCH 03/11] t: convert tests to use helpers for reference existence Patrick Steinhardt
2023-10-18 16:28 ` Junio C Hamano
2023-10-18 5:35 ` [PATCH 04/11] t: convert tests to not write references via the filesystem Patrick Steinhardt
2023-10-18 18:34 ` Junio C Hamano
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-23 19:10 ` Junio C Hamano
2023-10-18 21:18 ` Junio C Hamano
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 05/11] t: convert tests to not access symrefs " Patrick Steinhardt
2023-10-20 19:52 ` Junio C Hamano
2023-10-18 5:35 ` [PATCH 06/11] t: convert tests to not access reflog " Patrick Steinhardt
2023-10-21 23:13 ` Junio C Hamano
2023-10-18 5:35 ` [PATCH 07/11] t1450: convert tests to remove worktrees via git-worktree(1) Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 08/11] t4207: delete replace references via git-update-ref(1) Patrick Steinhardt
2023-10-18 13:27 ` Han-Wen Nienhuys
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-23 16:42 ` Taylor Blau
2023-10-24 6:42 ` Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 09/11] t7300: assert exact states of repo Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 10/11] t7900: assert the absence of refs via git-for-each-ref(1) Patrick Steinhardt
2023-10-18 5:35 ` [PATCH 11/11] t: mark several tests that assume the files backend with REFFILES Patrick Steinhardt
2023-10-18 5:39 ` [PATCH 00/11] t: reduce direct disk access to data structures Patrick Steinhardt
2023-10-18 23:40 ` Junio C Hamano
2023-10-23 11:57 ` Patrick Steinhardt
2023-10-18 15:32 ` Junio C Hamano
2023-10-19 10:13 ` Han-Wen Nienhuys [this message]
2023-10-19 17:55 ` Junio C Hamano
2023-10-23 13:58 ` Patrick Steinhardt
2023-10-24 14:04 ` [PATCH v2 0/9] " Patrick Steinhardt
2023-10-24 14:04 ` [PATCH v2 1/9] t: allow skipping expected object ID in `ref-store update-ref` Patrick Steinhardt
2023-10-24 14:04 ` [PATCH v2 2/9] t: convert tests to not write references via the filesystem Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 3/9] t: convert tests to not access symrefs " Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 4/9] t: convert tests to not access reflog " Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 5/9] t1450: convert tests to remove worktrees via git-worktree(1) Patrick Steinhardt
2023-10-27 2:42 ` Eric Sunshine
2023-10-24 14:05 ` [PATCH v2 6/9] t4207: delete replace references via git-update-ref(1) Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 7/9] t7300: assert exact states of repo Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 8/9] t7900: assert the absence of refs via git-for-each-ref(1) Patrick Steinhardt
2023-10-24 14:05 ` [PATCH v2 9/9] t: mark several tests that assume the files backend with REFFILES Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 0/9] t: reduce direct disk access to data structures Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 1/9] t: allow skipping expected object ID in `ref-store update-ref` Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 2/9] t: convert tests to not write references via the filesystem Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 3/9] t: convert tests to not access symrefs " Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 4/9] t: convert tests to not access reflog " Patrick Steinhardt
2023-11-02 8:46 ` [PATCH v3 5/9] t1450: convert tests to remove worktrees via git-worktree(1) Patrick Steinhardt
2023-11-02 8:47 ` [PATCH v3 6/9] t4207: delete replace references via git-update-ref(1) Patrick Steinhardt
2023-11-02 8:47 ` [PATCH v3 7/9] t7300: assert exact states of repo Patrick Steinhardt
2023-11-02 8:47 ` [PATCH v3 8/9] t7900: assert the absence of refs via git-for-each-ref(1) Patrick Steinhardt
2023-11-02 8:47 ` [PATCH v3 9/9] t: mark several tests that assume the files backend with REFFILES Patrick Steinhardt
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