Add support for pgTap extension?

[jens-f]

Pglite is fantastic for running tests due to it's speed.

Would you consider adding support for pgTap? It requires loading this extension which is not currently available in the list of supported extensions:

CREATE EXTENSION IF NOT EXISTS pgtap;

Due to it's comprehensive assertion support and running directly inside postgres it would be a powerful addition to pglite.

[tdrz]

Hey @jens-f thank you for this!

We're open to PRs! If you want to give it a try, have a look at how other extensions like pg_ivm or pg_vector are integrated with PGlite.

[jens-f]

Do you have any pointers on how to get started and what is involved in this process? Even a link to explanations how these extensions needed to be changed could be helpful. The pglite documentation doesn't seem to cover any of this but might be a good enabler for the community

[tdrz]

I will try to spend some time in the coming days to document how to approach adding a new extension.

pgTap seems to be on the happy path (but unsure until we have a comprehensive test), I added a draft PR for it: #818

@jens-f could please extend the test in packages/pglite/tests/pgtap.test.ts as the only thing it does right now is to load the extension?

[tdrz]

Can also be played with here: https://68f37e78e347466e85d2526f--pglite.netlify.app/repl/

[jens-f]

@tdrz this is amazing! Thank you so much for adding this so quickly. The new pgtap extension works as expected, just sent a PR to add a couple of tests for it #821

[MH4GF]

@tdrz @jens-f
Hi! 👋 I was planning to submit a PR for pgTAP support, but found this issue and PR #818 while searching - looks like I'm a bit late! 😅

Background

We're building an AI agent for database management (Liam AI), and we've implemented pgTAP with PGlite to generate and execute database tests.

• Implementation: https://github.com/liam-hq/liam/tree/main/frontend/internal-packages/pglite-server/src/extensions/pgtap
• Demo: ✨(agent): Add pgTAP test support for QA test generation liam-hq/liam#3837 (comment)

How I Can Help

Even though PR #818 is already in progress, I'd be happy to help with reviews or testing if needed!

[tdrz]

Hi @MH4GF !

I'd be happy to help with reviews or testing if needed!

That's very nice, thank you!

Re testing, please have a look at the tests that @jens-f added and I already merged in #818 . If there are any additional (corner) cases that need to be covered, please feel free to open a PR on top of that. Otherwise I think this is fine.

Re review, there is a frontend and a backend part to every extension in PGlite. Here is the backend part for pgTAP: electric-sql/postgres-pglite#51

Reviewing both fe and be is a good intro to adding extensions in PGlite, feel free to have a go at it! Same for @jens-f or anyone else interested in contributing new extensions!

[MH4GF]

@tdrz cc @jens-f Thanks! I've reviewed both PRs. The tests are thorough and well-written—great work.
Once these two PRs are merged and released, I'll immediately verify there are no edge case issues in our product 🙋‍♂️

[jens-f]

Thanks @tdrz for the link to the backend PR, that clarified a number of questions for me.

[tdrz]

Released in v0.3.12.

[MH4GF]

liam-hq/liam#3983 It works fine and seems like it can be replaced. If there are any issues, I'll submit a pull request!