test(workflow-execution-service): cover ResultExportService helpers

[Ma77Ball]

What changes were proposed in this PR?

• Add ResultExportServiceSpec covering parseOperators deserialization, empty-array round-trip, and malformed-input failure.
• Cover validateExportRequest returning a 400 response when no operators are selected and None otherwise.

Any related issues, documentation, discussions?

Closes: #6704

How was this PR tested?

• Run: sbt "WorkflowExecutionService/testOnly *ResultExportServiceSpec", expect all 5 tests passing.
• Test-only change; no production code is modified.

Was this PR authored or co-authored using generative AI tooling?

Co-authored with Claude Opus 4.8 in compliance with ASF

[github-actions]

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[github-actions]

⚠️ Benchmark changes need a look

🟢 0 better · 🔴 2 worse · ⚪ 13 noise (<±5%) · 0 without baseline

Compared against main 0467c76 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

	config	throughput	MB/s	latency	max Δ latest / 7d
🔴	bs=10 sw=10 sl=64	396	0.241	24,479/36,080/36,080 us	🔴 +7.3% / 🔴 +128.2%
⚪	bs=100 sw=10 sl=64	805	0.491	123,255/150,297/150,297 us	⚪ within ±5% / 🔴 +43.1%
⚪	bs=1000 sw=10 sl=64	926	0.565	1,080,412/1,105,202/1,105,202 us	⚪ within ±5% / 🔴 +12.1%

Baseline details

Latest main 0467c76 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	396 tuples/sec	409 tuples/sec	769.76 tuples/sec	-3.2%	-48.6%
bs=10 sw=10 sl=64	MB/s	0.241 MB/s	0.25 MB/s	0.47 MB/s	-3.6%	-48.7%
bs=10 sw=10 sl=64	p50	24,479 us	24,682 us	12,663 us	-0.8%	+93.3%
bs=10 sw=10 sl=64	p95	36,080 us	33,611 us	15,813 us	+7.3%	+128.2%
bs=10 sw=10 sl=64	p99	36,080 us	33,611 us	19,001 us	+7.3%	+89.9%
bs=100 sw=10 sl=64	throughput	805 tuples/sec	807 tuples/sec	1,009 tuples/sec	-0.2%	-20.3%
bs=100 sw=10 sl=64	MB/s	0.491 MB/s	0.493 MB/s	0.616 MB/s	-0.4%	-20.3%
bs=100 sw=10 sl=64	p50	123,255 us	122,187 us	99,444 us	+0.9%	+23.9%
bs=100 sw=10 sl=64	p95	150,297 us	150,174 us	105,012 us	+0.1%	+43.1%
bs=100 sw=10 sl=64	p99	150,297 us	150,174 us	116,467 us	+0.1%	+29.0%
bs=1000 sw=10 sl=64	throughput	926 tuples/sec	906 tuples/sec	1,044 tuples/sec	+2.2%	-11.3%
bs=1000 sw=10 sl=64	MB/s	0.565 MB/s	0.553 MB/s	0.637 MB/s	+2.2%	-11.3%
bs=1000 sw=10 sl=64	p50	1,080,412 us	1,096,025 us	964,034 us	-1.4%	+12.1%
bs=1000 sw=10 sl=64	p95	1,105,202 us	1,143,147 us	1,007,497 us	-3.3%	+9.7%
bs=1000 sw=10 sl=64	p99	1,105,202 us	1,143,147 us	1,040,936 us	-3.3%	+6.2%

Raw CSV

config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,505.69,200,128000,396,0.241,24478.70,36079.82,36079.82
1,100,10,64,20,2483.69,2000,1280000,805,0.491,123255.01,150296.55,150296.55
2,1000,10,64,20,21599.76,20000,12800000,926,0.565,1080412.17,1105201.58,1105201.58

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.84%. Comparing base (0467c76) to head (0377966).
⚠️ Report is 31 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6705      +/-   ##
============================================
+ Coverage     74.65%   74.84%   +0.18%     
- Complexity     3438     3450      +12     
============================================
  Files          1160     1160              
  Lines         45793    45793              
  Branches       5069     5069              
============================================
+ Hits          34189    34276      +87     
+ Misses         9953     9863      -90     
- Partials       1651     1654       +3     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from 100267c
agent-service	76.76% <ø> (ø)		Carriedforward from 100267c
amber	67.32% <ø> (+0.51%)	⬆️
computing-unit-managing-service	18.00% <ø> (ø)		Carriedforward from 100267c
config-service	66.66% <ø> (ø)		Carriedforward from 100267c
file-service	66.80% <ø> (ø)		Carriedforward from 100267c
frontend	78.56% <ø> (ø)		Carriedforward from 100267c
notebook-migration-service	78.94% <ø> (ø)		Carriedforward from 100267c
pyamber	91.99% <ø> (ø)		Carriedforward from 100267c
workflow-compiling-service	55.14% <ø> (ø)		Carriedforward from 100267c

*This pull request uses carry forward flags. Click here to find out more.

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[Copilot]

Pull request overview

Adds Scala unit tests for ResultExportService request helper methods in the Amber web service layer, improving coverage for operator JSON parsing and request validation logic without modifying production code.

Changes:

• Added ResultExportServiceSpec to test parseOperators JSON deserialization (including empty array and malformed input).
• Added tests for validateExportRequest returning 400 Bad Request when no operators are selected, and None otherwise.

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[aglinxinyuan]

LGTM!