Missing FileDataSink test in etdump_flatcc tests

[Gasoonjia]

🚀 The feature, motivation and pitch

We have adopted datasink as the primary output data dumping pipeline in ETDumpGen, and we've implemented two datasinks, BufferDataSink and FileDataSink. #9033 has more details.
However, we only tested BufferDataSink in the ETDumpGen's test (e.g. https://github.com/pytorch/executorch/blob/main/devtools/etdump/tests/etdump_test.cpp#L237) but still missing FileDataSink test.
So, for this issue we'd love to bring FileDataSink into ETDumpGen's test.
You can mimic what we've done for BufferDataSink to solve the problem, and https://github.com/pytorch/executorch/blob/main/extension/data_loader/test/file_data_loader_test.cpp would be a good example about how to create a temporary file for testing.

Alternatives

No response

Additional context

No response

RFC (Optional)

No response

cc @Jack-Khuu

[Megan0704-1]

Hello!
This is my first time contributing to this repository, and I’d love to work on this issue.
Could you assign it to me?
I plan to refer to the example and follow the BufferDataSink test structure to implement the solution.

[Gasoonjia]

yes of course! Thanks for your contribution! @Megan0704-1
Please let me know if anything i can help, or reach out to me via our discord!

[Megan0704-1]

Hi @Gasoonjia
I’ve addressed it in PR #9332, which adds FileDataSink validation to the etdump_test.cpp debug event tests.
The changes include:

• Extending test loops to cover all 3 data sink types (span/buffer/file)
• Adding temporary file creation/cleanup logic
• Ensuring CMake linkage for FileDataSink
  Could you please review the PR when you have time?
  Let me know if there’s anything I missed or if additional test cases would be helpful.

Thanks for the clear issue description—it made the fix straightforward! 🙌

[Gasoonjia]

Thanks @Megan0704-1 for your contribution! Have left some comments under your PR.