fix how tests create service subprocess (causes errors with new cuda)

[tmckayus]

Recent changes in CUDA and related Python libraries exposed a bug in cuOpt service tests where subprocesses to run the server were started without a full copy of the parent environment. This omitted things like the CONDA path, etc. Previously this was harmless, but library loading code in CUDA is more sophisticated now and missing env vars cause unexpected errors.

Summary by CodeRabbit

• Tests
  • Refactored test server startup configuration to use explicit command-line arguments instead of environment variables for improved test flexibility and reliability.

[coderabbitai]

📝 Walkthrough

Walkthrough

Three test files were updated to migrate from hardcoded environment variable configuration to command-line argument configuration for the cuopt server process. Changes include adding os imports, replacing static environment dictionaries with os.environ.copy(), and updating server invocation to use explicit CLI flags (-i, -p, -l) instead of environment variables.

Changes

Cohort / File(s)	Summary
Test Configuration Migration python/cuopt_server/cuopt_server/tests/test_bill_logging.py, python/cuopt_server/cuopt_server/tests/test_server_health.py, python/cuopt_server/cuopt_server/tests/utils/utils.py	Migrated cuopt server process startup from environment variable configuration to command-line arguments. Updated environment handling to use os.environ.copy() with selective overrides and changed server invocation to pass explicit host, port, and log level via CLI flags (-i, -p, -l).

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly addresses the main change: fixing how tests create service subprocesses to work with new CUDA by passing full environment to child processes instead of partial environment variables.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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[coderabbitai]

🧹 Nitpick comments (1)

python/cuopt_server/cuopt_server/tests/utils/utils.py (1)

315-316: Consider narrowing fixture scope to reduce inter-test contamination.

scope="session" means all tests share one server process for the entire pytest run. Queued requests, cached responses, or GPU allocations from an earlier test can silently influence later ones. Switching to scope="module" (or adding an explicit request-flush/health-reset call in the fixture's teardown) would better align with the test isolation requirement.

As per coding guidelines: "Ensure test isolation: prevent GPU state, cached memory, and global variables from leaking between test cases; verify each test independently initializes its environment."

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@python/cuopt_server/cuopt_server/tests/utils/utils.py` around lines 315 -
316, The cuoptproc pytest fixture currently uses scope="session" which lets one
server process be shared across all tests; change the fixture declaration for
cuoptproc to scope="module" (or, alternatively, add explicit teardown/reset
logic inside the cuoptproc fixture that flushes queued requests, clears GPU
state, and/or calls the server health-reset API between tests) so each module
gets an isolated server instance; update the decorator on the cuoptproc fixture
and/or add calls to the server reset/cleanup functions in its teardown block to
ensure no cached responses, queued requests, or GPU allocations persist across
tests.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@python/cuopt_server/cuopt_server/tests/utils/utils.py`:
- Around line 315-316: The cuoptproc pytest fixture currently uses
scope="session" which lets one server process be shared across all tests; change
the fixture declaration for cuoptproc to scope="module" (or, alternatively, add
explicit teardown/reset logic inside the cuoptproc fixture that flushes queued
requests, clears GPU state, and/or calls the server health-reset API between
tests) so each module gets an isolated server instance; update the decorator on
the cuoptproc fixture and/or add calls to the server reset/cleanup functions in
its teardown block to ensure no cached responses, queued requests, or GPU
allocations persist across tests.

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ℹ️ Review info

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between fcfd4f0 and 6a5d662.

📒 Files selected for processing (3)

• python/cuopt_server/cuopt_server/tests/test_bill_logging.py
• python/cuopt_server/cuopt_server/tests/test_server_health.py
• python/cuopt_server/cuopt_server/tests/utils/utils.py

[tmckayus]

/merge