tests: serialize shared mock server access

[jbeckwith-oai]

Summary

• Serialize every test using the shared Steady mock server across JUnit threads and Gradle worker JVMs.
• Add a process-local lock plus a URL-scoped OS file lock in TestServerExtension.
• Keep the fix entirely in the test harness; no CI workflow changes.
• Generalize and supersede the conversation-item-only approach in tests: serialize conversation item service tests #813.

Root cause

The generated output_text payload is valid Steady data. Seed 1 makes the failure reproducible under concurrent blocking/async service classes, but the isolated async test and high-volume in-process deserialization both pass. The failure occurs when separate Gradle workers access the persistent mock concurrently, so a JUnit-only resource lock cannot fully coordinate it. This is the same underlying race topology as the conversation-item flake covered by #813.

Validation

• Reproduced the response service pair failure before the fix (immediate at seed 1).
• Response blocking/async pair: 30/30 post-fix passes.
• Conversation-item blocking/async pair: 30/30 post-fix passes.
• :openai-java-core:lintKotlin passes.
• Full JDK 21 core suite passes: 6,268 tests, 0 failures, 20 skipped.
• Full Jackson compatibility suite passes: 5,629 tests, 0 failures.

[Copilot]

Pull request overview

This PR updates the JUnit test harness to prevent concurrent access to the shared Steady mock server across both JUnit parallel execution and separate Gradle test-worker JVMs, addressing cross-process race flakes without changing CI workflows.

Changes:

• Add a process-local fair ReentrantLock to serialize mock-server tests within a single JVM.
• Add a URL-scoped OS-backed file lock (in ${java.io.tmpdir}) to coordinate serialization across Gradle worker JVMs.
• Apply serialization by implementing InvocationInterceptor in TestServerExtension to wrap each test method invocation.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 17.276s for Java SDK PR #815.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	209ms
tests/chat-completions-create.test.ts	✅ Passed	669ms
tests/chat-completions-stream.test.ts	✅ Passed	379ms
tests/files-content-binary.test.ts	✅ Passed	229ms
tests/files-create-multipart.test.ts	✅ Passed	395ms
tests/files-list-pagination.test.ts	✅ Passed	330ms
tests/initialize-config.test.ts	✅ Passed	201ms
tests/instance-isolation.test.ts	✅ Passed	281ms
tests/models-list.test.ts	✅ Passed	174ms
tests/responses-background-lifecycle.test.ts	✅ Passed	867ms
tests/responses-body-method-errors.test.ts	✅ Passed	476ms
tests/responses-cancel-timeout.test.ts	✅ Passed	245ms
tests/responses-cancel.test.ts	✅ Passed	357ms
tests/responses-compact-retries.test.ts	✅ Passed	593ms
tests/responses-compact.test.ts	✅ Passed	256ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	360ms
tests/responses-create-advanced.test.ts	✅ Passed	1.377s
tests/responses-create-disconnect.test.ts	✅ Passed	1.14s
tests/responses-create-errors.test.ts	✅ Passed	342ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	280ms
tests/responses-create-retries.test.ts	✅ Passed	480ms
tests/responses-create-stream-failures.test.ts	✅ Passed	201ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	244ms
tests/responses-create-stream-wire.test.ts	✅ Passed	6.51s
tests/responses-create-stream.test.ts	✅ Passed	687ms
tests/responses-create-terminal-states.test.ts	✅ Passed	328ms
tests/responses-create-timeout.test.ts	✅ Passed	291ms
tests/responses-create.test.ts	✅ Passed	249ms
tests/responses-delete.test.ts	✅ Passed	257ms
tests/responses-input-items-errors.test.ts	✅ Passed	266ms
tests/responses-input-items-list.test.ts	✅ Passed	299ms
tests/responses-input-items-options.test.ts	✅ Passed	636ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	231ms
tests/responses-input-tokens-count.test.ts	✅ Passed	402ms
tests/responses-malformed-inputs.test.ts	✅ Passed	5.351s
tests/responses-not-found-errors.test.ts	✅ Passed	323ms
tests/responses-parse.test.ts	✅ Passed	837ms
tests/responses-retrieve-retries.test.ts	✅ Passed	262ms
tests/responses-retrieve.test.ts	✅ Passed	316ms
tests/responses-stored-method-errors.test.ts	✅ Passed	1s
tests/retry-behavior.test.ts	✅ Passed	3.54s
tests/sdk-error-shape.test.ts	✅ Passed	461ms

View OkTest run #30059874669

_{SDK merge (4bebb0f71e05) · head (be3672b435aa) · base (a3a50ec79890) · OkTest (d2b5921fc22a)}

[HAYDEN-OAI]

Reviewed the shared mock-server locking path and the #813 context. The URL-scoped OS lock plus process-local lock cleanly serializes the current TestServerExtension-backed test methods across worker JVMs and JUnit threads. No actionable correctness or maintainability issues found.