Hey David, Yeah, I think in terms of scope I aim for more providing a framework for unit testing the behavior of custom PTFs. I'd like to include as much validation as possible but there might be validation steps that aren't possible to do without dipping into the engine side of things.
I'm not entirely sure on the real/processing time considerations - my aim here was mostly around letting users validate timer behaviour, and timer registration/firing in PTFs is based on watermarks, if I read the doc correctly. Kind regards, Mika On Wed, 4 Mar 2026, at 10:38 AM, David Radley wrote: > Hi Mika, > This sounds like a good idea, in terms of scope, Is the idea that this is > purely for unit tests or is this additionally proposed as validation / test > harness for use when developing custom PTFs. > I guess this allows us to create a common set of tests that all PTFs need to > pass using this harness. > > I would assume there are real (not event) time considerations for some PTFs, > it would be worth mentioning how we should handle that. > > Kind regards, David. > > From: Mika Naylor <[email protected]> > Date: Tuesday, 3 March 2026 at 16:46 > To: [email protected] <[email protected]> > Subject: [EXTERNAL] [DISCUSS] FLIP-567: Introduce a ProcessTableFunction Test > Harness > > Hey everyone! > > I would like to kick off a discussion on FLIP-567: Introduce a > ProcessTableFunction Test Harness[1]. > > Currently, testing PTFs require full integration tests against a running > Flink cluster. This FLIP would introduce a developer-friendly test harness > for unit testing PTFs and would provide introspection to output, state, > timers, and watermarks for assertions and behaviour validation. This would > let developers iterate and test their PTFs without needing to run a fullscale > integration test against a live Flink cluster. > > Would love any thoughts and feedback the community might have on this > proposal. > > Kind regards, > Mika Naylor > > [1] > https://cwiki.apache.org/confluence/display/FLINK/FLIP-567%3A+Introduce+a+ProcessTableFunction+Test+Harness > > Unless otherwise stated above: > > IBM United Kingdom Limited > Registered in England and Wales with number 741598 > Registered office: Building C, IBM Hursley Office, Hursley Park Road, > Winchester, Hampshire SO21 2JN >
