Engineering work
Applied researchPublic preprint

EventFlowSentry

A reproducible fault-injection and metamorphic-testing approach for finding event-time failures in streaming pipelines.

Event-time streamingFault injectionMetamorphic testingReproducibility

01

Problem

Event-time systems can appear correct in ordinary tests while producing different outcomes under late data, reordering, replay, watermark movement, and recovery. The hard part is not generating random failures; it is producing faults whose expected invariants and evidence remain reproducible.

Constraints that shaped the design

  • Keep experiments repeatable enough for independent inspection.
  • Exercise timing and recovery behavior without coupling the method to one production stack.
  • Separate observed behavior from claims that require broader empirical validation.

02

Architecture

  1. 01

    Controlled fault model

    Represent event-time perturbations as explicit, repeatable experimental inputs.

  2. 02

    Metamorphic oracle

    Compare related executions through invariants when a single expected output is insufficient.

  3. 03

    Evidence trail

    Retain the execution conditions and resulting observations for analysis and reproduction.

03

Design decisions

  • Treat reproducibility as part of the test design, not an after-the-fact reporting step.
  • Use metamorphic relations to test semantics that are difficult to express as fixed expected outputs.
  • Describe the artifact conservatively as a preprint until peer review and external replication change its status.

04

Alternatives considered

  • Purely random chaos tests without replayable fault definitions.
  • Happy-path examples that do not vary event-time or recovery conditions.
  • Presenting repository activity or manuscript submission as proof of independent impact.

05

Testing and results

  • The methodology, motivation, and reported evaluation are documented in the public SSRN manuscript.
  • The DOI provides a stable external identifier for the current preprint version.
  • Claims on this page are intentionally bounded by the public artifact; external adoption is not asserted.

Outcome

The work turns timing faults into an inspectable systems-testing problem and provides a public research artifact that readers can evaluate directly.

06

Limitations

  • The current public evidence is a preprint, not an accepted publication.
  • Results should not be generalized beyond the evaluated systems and fault models without replication.

07

Lessons learned

  • A fault is useful only when the resulting behavior can be explained and replayed.
  • Event-time correctness needs relationships between executions, not only example-by-example assertions.