test(amber): cover websocket session state

[aglinxinyuan]

What changes were proposed in this PR?

Adds focused unit coverage for websocket event delivery, workflow-service subscription replacement and cleanup, session-map removal, and computing-unit access state.

Any related issues, documentation, discussions?

Closes #7153

How was this PR tested?

• WorkflowExecutionService/testOnly org.apache.texera.web.SessionStateSpec — 3 succeeded.
• WorkflowExecutionService/Test/scalafmtCheck and WorkflowExecutionService/Test/scalafix --check.

Mutation proof:

Production mutation	Result
Replaced the serialized websocket payload with an empty string	1 test failed
Stopped retaining the subscribed workflow service	1 test failed
Stopped removing a session from the session-state map	1 test failed

Each mutation was reverted before the final green test run.

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

Generated-by: Codex (GPT-5)

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• No candidates found from git blame history.

[github-actions]

⚠️ Benchmark changes need a look

🟢 2 better · 🔴 6 worse · ⚪ 7 noise (<±5%) · 0 without baseline

Compared against main 45b7b20 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	544	0.332	17,217/26,538/26,538 us	🔴 +13.1% / 🔴 +63.8%
🔴	bs=100 sw=10 sl=64	1,216	0.742	83,393/93,447/93,447 us	🟢 -25.9% / 🟢 +26.0%
🔴	bs=1000 sw=10 sl=64	1,434	0.876	697,493/838,437/838,437 us	🔴 +12.8% / 🟢 +44.6%

Baseline details

Latest main 45b7b20 from same runner

config	metric	PR	latest main	7d avg	Δ latest	Δ 7d
bs=10 sw=10 sl=64	throughput	544 tuples/sec	589 tuples/sec	765.25 tuples/sec	-7.6%	-28.9%
bs=10 sw=10 sl=64	MB/s	0.332 MB/s	0.36 MB/s	0.467 MB/s	-7.8%	-28.9%
bs=10 sw=10 sl=64	p50	17,217 us	15,220 us	12,703 us	+13.1%	+35.5%
bs=10 sw=10 sl=64	p95	26,538 us	27,825 us	16,199 us	-4.6%	+63.8%
bs=10 sw=10 sl=64	p99	26,538 us	27,825 us	19,557 us	-4.6%	+35.7%
bs=100 sw=10 sl=64	throughput	1,216 tuples/sec	1,187 tuples/sec	965.22 tuples/sec	+2.4%	+26.0%
bs=100 sw=10 sl=64	MB/s	0.742 MB/s	0.725 MB/s	0.589 MB/s	+2.3%	+25.9%
bs=100 sw=10 sl=64	p50	83,393 us	77,114 us	103,830 us	+8.1%	-19.7%
bs=100 sw=10 sl=64	p95	93,447 us	126,179 us	110,778 us	-25.9%	-15.6%
bs=100 sw=10 sl=64	p99	93,447 us	126,179 us	118,713 us	-25.9%	-21.3%
bs=1000 sw=10 sl=64	throughput	1,434 tuples/sec	1,412 tuples/sec	992.33 tuples/sec	+1.6%	+44.5%
bs=1000 sw=10 sl=64	MB/s	0.876 MB/s	0.862 MB/s	0.606 MB/s	+1.6%	+44.6%
bs=1000 sw=10 sl=64	p50	697,493 us	722,815 us	1,016,959 us	-3.5%	-31.4%
bs=1000 sw=10 sl=64	p95	838,437 us	743,123 us	1,062,501 us	+12.8%	-21.1%
bs=1000 sw=10 sl=64	p99	838,437 us	743,123 us	1,082,611 us	+12.8%	-22.6%

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
0,10,10,64,20,367.56,200,128000,544,0.332,17217.40,26537.61,26537.61
1,100,10,64,20,1644.92,2000,1280000,1216,0.742,83393.28,93446.51,93446.51
2,1000,10,64,20,13942.78,20000,12800000,1434,0.876,697492.71,838437.00,838437.00

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.64%. Comparing base (45b7b20) to head (e8282c9).
⚠️ Report is 11 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #7157      +/-   ##
============================================
+ Coverage     79.62%   80.64%   +1.02%     
- Complexity     3836     3908      +72     
============================================
  Files          1160     1160              
  Lines         46188    46188              
  Branches       5145     5145              
============================================
+ Hits          36777    37249     +472     
+ Misses         7778     7275     -503     
- Partials       1633     1664      +31     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from 03d2b6c
agent-service	77.42% <ø> (ø)		Carriedforward from 03d2b6c
amber	75.86% <ø> (+2.77%)	⬆️
computing-unit-managing-service	20.49% <ø> (ø)		Carriedforward from 03d2b6c
config-service	65.97% <ø> (ø)		Carriedforward from 03d2b6c
file-service	66.80% <ø> (ø)		Carriedforward from 03d2b6c
frontend	83.16% <ø> (ø)		Carriedforward from 03d2b6c
notebook-migration-service	78.89% <ø> (ø)		Carriedforward from 03d2b6c
pyamber	97.36% <ø> (ø)		Carriedforward from 03d2b6c
workflow-compiling-service	26.31% <ø> (ø)		Carriedforward from 03d2b6c

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

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[mengw15]

LGTM

[Copilot]

Pull request overview

Adds a new Amber unit-test spec to validate server-side websocket session state behavior, aligning with the Amber web layer’s SessionState responsibilities (event delivery + workflow-service subscription lifecycle + session registry + computing-unit privilege state).

Changes:

• Introduces SessionStateSpec covering websocket JSON event serialization via SessionState.send.
• Adds coverage for workflow-service subscription replacement / cleanup via SessionState.subscribe + unsubscribe.
• Adds coverage for session registry operations (setState / getState / removeState) and computing-unit access state behavior.

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