Hello all, BEAM-775 aims to remove Aggregators from the Java SDK. One of the blocking issues is BEAM-1148, porting PAssert away from using them. Let me summarize the issues that we should consider; and then propose a solution that seems reasonable:
1. We want the test Pipeline run to fail-fast in the case of a failed assertion. 2. We want the test Pipeline run to fail if not all of the assertions were executed. This catches bugs that would otherwise be hidden. 3. We want to provide a simple default implementation for PAssert. Metrics are not supported by all runners and when they are both of committed/attempted values may not be available.ut they seem like a reasonable default mechanism to count success/failure of assertions. With this in mind, I propose the following: 1. The mechanism to count/check assertions will be a composite PTransform that receives the results from the PAssert transforms. Test runners will be able to override the implementiation of this PTransform. * The current asserting DoFns in PAssert will go from being DoFn<ActualT, Void> to be DoFn<ActualT, SuccesOrFailure>, and pass the output SuccessOrFailure objects downstream to the checking PTransform<SuccessOrFailure, Void>. * This default PTransform<SuccessOrFailure, Void> will use metrics to count successes, and fail immediately on failures (after incrementing the failure counter). 2. A test runner can override the default implementations of this PTransform using the graph surgery API. 3. Every TestXRunner implements its own PAssert verification, so we may need to change that individually - though these changes are not likely to be very significant for the existing runners. What are your thoughts? If everyone is okay with this proposed idea, I will go ahead and implement it. Best -P.
