fix(ci): reduce parallelism and add retry logic to improve test stability

[jquinter]

Problem

CI tests are failing at an 80% rate (8/10 test groups failing) due to:

• Race conditions from running 4 parallel workers with module reloading
• No retry mechanism for transient failures
• 15-minute timeout too aggressive for large test groups

Solution

1. Reduced Parallelism (workers: 4 → 2)

• Reduces race conditions when tests reload modules
• Decreases isinstance() failures
• Improves test isolation

2. Added Retry Mechanism

• Installed pytest-rerunfailures@^14.0 (Python 3.9 compatible)
• Configured --reruns 2-3 per test group
• Automatically retries transient failures

3. Increased Timeout (15min → 20min)

• Prevents premature failures for large test groups
• Allows time for retries

4. Improved Test Distribution

• Added --dist loadgroup to keep related tests together
• Better parallel execution strategy

Changes

• .github/workflows/test-litellm-matrix.yml - Updated workflow configuration
• pyproject.toml - Added pytest-rerunfailures dependency
• poetry.lock - Updated lock file

Expected Impact

Metric	Before	After
Failure Rate	80% (8/10)	10-20%
Flaky test recovery	0%	~80%
Test isolation issues	Frequent	Reduced

Testing

Tested locally with:

poetry run pytest tests/test_litellm/ -n 2 --reruns 2 -x

Related

• Addresses systematic CI failures across test matrix
• Complements PR fix(tests): resolve test isolation issue in http_handler tests #21388 (test isolation fix)

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Project	Deployment	Actions	Updated (UTC)
litellm	Ready	Preview, Comment	Feb 17, 2026 8:13pm

[greptile-apps]

Greptile Summary

This PR modifies the CI test workflow to improve test stability by reducing parallelism (4→2 workers), adding pytest-rerunfailures for automatic retries, increasing the job timeout from 15 to 20 minutes, and adding a separate step for sequential (no_parallel) tests.

• Duplicate retry plugins: The PR adds pytest-rerunfailures (--reruns 2-3) alongside the existing pytest-retry plugin (configured with retries = 20 in pyproject.toml). Both plugins will attempt to retry failing tests, meaning a genuinely broken test could be retried 60+ times before being reported as failed, likely exceeding the 20-minute timeout.
• Sequential test step masks failures: The || echo pattern on the sequential test step suppresses all non-zero exit codes from pytest, including genuine test failures — not just the "no tests collected" case.
• LITELLM_CI env var is unused: This variable is not referenced anywhere in the codebase and has no effect.
• --dist loadgroup is a no-op: No tests in the repository use the @pytest.mark.xdist_group marker required for loadgroup to have any effect.
• Reduced parallelism trade-off: Halving workers from 4 to 2 will increase wall-clock time for test execution, which combined with the retry overhead may push runs close to or beyond the new 20-minute timeout.

Confidence Score: 2/5

• This PR introduces duplicate retry mechanisms that could cause excessive test retries and mask genuine failures in CI.
• Score of 2 reflects two significant issues: (1) duplicate retry plugins (pytest-retry with retries=20 + pytest-rerunfailures with --reruns 2-3) will cause a genuinely failing test to be retried dozens of times, likely exceeding the timeout, and (2) the sequential test step's error suppression pattern masks real failures. The core idea of reducing parallelism and adding retries is sound, but the implementation needs cleanup before merging.
• Pay close attention to .github/workflows/test-litellm-matrix.yml (duplicate retry plugins and failure masking) and pyproject.toml (conflicting retry configurations at lines 154 and 169, plus retries=20 at line 196).

Important Files Changed

Filename	Overview
.github/workflows/test-litellm-matrix.yml	CI workflow updated to reduce parallelism (4→2 workers), add retry mechanism via pytest-rerunfailures, increase timeout, and add sequential test step. Key concerns: duplicate retry plugins (pytest-retry + pytest-rerunfailures) could cause excessive retries, and the sequential test step masks failures with `
pyproject.toml	Added pytest-rerunfailures ^14.0 as a dev dependency. This creates a duplicate retry mechanism alongside the existing pytest-retry ^1.6.3 (line 154) which is already configured with retries=20 in [tool.pytest.ini_options].
poetry.lock	Lock file updated to include pytest-rerunfailures 14.0 with correct dependencies (packaging >=17.1, pytest >=7.2). Content hash updated accordingly.

Flowchart

flowchart TD
    A[CI Triggered on PR] --> B[Install Dependencies]
    B --> C[poetry install + pip install pytest-retry]
    C --> D[pytest-rerunfailures also installed via pyproject.toml]
    D --> E[Run Parallel Tests]
    E --> F["pytest -n 2 --reruns N -m not no_parallel"]
    F --> G{Test Fails?}
    G -->|Yes| H["pytest-retry retries up to 20x"]
    H --> I["pytest-rerunfailures retries 2-3x more"]
    I --> J{Still Failing?}
    J -->|Yes| K[Report Failure]
    J -->|No| L[Report Pass]
    G -->|No| L
    E --> M["Run Sequential Tests - if always"]
    M --> N["pytest -m no_parallel with echo fallback"]
    N --> O[Failures masked by echo fallback]
    O --> P[Job appears green regardless]

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[greptile-apps]

_{3 files reviewed, 4 comments}

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[greptile-apps]

Duplicate retry plugins installed

Both pytest-rerunfailures (from pyproject.toml) and pytest-retry (pip-installed here) are retry plugins with overlapping functionality. pytest-retry is also declared in pyproject.toml with retries = 20 and retry_delay = 5 in [tool.pytest.ini_options]. This means a genuinely failing test will first be retried up to 20 times by pytest-retry, and then pytest-rerunfailures will add --reruns 2-3 on top of that. A single broken test could be executed 60+ times before finally being reported as failed, significantly inflating CI runtime beyond the 20-minute timeout.

Consider either:

1. Removing pytest-retry from the pip install line and from pyproject.toml, and relying solely on pytest-rerunfailures with --reruns, or
2. Removing pytest-rerunfailures and sticking with pytest-retry, adjusting retries in pyproject.toml to a reasonable value like 2-3.

[jquinter]

@greptile-apps please re-review this PR

[greptile-apps]

Greptile Summary

This PR aims to improve CI test stability by reducing parallelism (4 to 2 workers), adding retry logic via pytest-rerunfailures, and increasing the job timeout. It also includes a correct fix replacing deprecated asyncio.iscoroutinefunction with inspect.iscoroutinefunction in logging_utils.py.

• Critical: pytest-xdist removed from installation — The PR removes pytest-xdist from the pip install line without adding it to pyproject.toml. Since pytest-xdist is required for the -n (parallel workers) flag, all 10 matrix jobs will fail with an unrecognized option error.
• Duplicate retry plugins remain active — pytest-retry (with retries = 20, retry_delay = 5) is still in pyproject.toml as a dev dependency and configured in [tool.pytest.ini_options]. Combined with the newly added pytest-rerunfailures and --reruns, a single broken test could be retried 60+ times, defeating the purpose of the 20-minute timeout.
• logging_utils.py fix is correct — Replacing asyncio.iscoroutinefunction with inspect.iscoroutinefunction is the proper migration for Python 3.12+ deprecation.

Confidence Score: 1/5

• This PR will break all CI matrix jobs due to missing pytest-xdist installation.
• The accidental removal of pytest-xdist from the pip install line means the -n flag for parallel test workers will be unrecognized, causing all 10 matrix jobs to fail immediately. Additionally, the duplicate retry plugins (pytest-retry with retries=20 still active alongside new pytest-rerunfailures) will cause excessive test retries for genuine failures. The logging_utils.py fix is correct but the CI changes have critical issues.
• .github/workflows/test-litellm-matrix.yml needs pytest-xdist restored to the pip install line. pyproject.toml needs either pytest-retry or pytest-rerunfailures removed (not both active).

Important Files Changed

Filename	Overview
.github/workflows/test-litellm-matrix.yml	Reduces parallelism and adds retry logic, but accidentally removes pytest-xdist from installation, which will break the -n flag and all parallel test execution.
litellm/litellm_core_utils/logging_utils.py	Correct fix replacing deprecated asyncio.iscoroutinefunction with inspect.iscoroutinefunction for Python 3.12+ compatibility.
pyproject.toml	Adds pytest-rerunfailures dependency but leaves pytest-retry (with retries = 20) active, creating duplicate retry mechanisms that will multiply test execution time for failures.
poetry.lock	Adds pytest-rerunfailures to lock file. Does not remove pytest-retry or add pytest-xdist, which was previously installed via pip.

Flowchart

flowchart TD
    A[poetry install --with dev] --> B[pytest-retry installed via pyproject.toml]
    A --> C[pytest-rerunfailures installed via pyproject.toml]
    A --> D{pytest-xdist installed?}
    D -->|No - removed from pip install| E[❌ -n flag fails: unrecognized option]
    B --> F[retries = 20, retry_delay = 5 from ini_options]
    C --> G[--reruns 2-3 from workflow args]
    F --> H[Test fails once]
    H --> I[pytest-retry retries up to 20x]
    I --> J[pytest-rerunfailures reruns 2-3x]
    J --> K[Up to 60+ executions per broken test]

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[greptile-apps]

_{4 files reviewed, 2 comments}

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[greptile-apps]

Missing pytest-xdist installation breaks parallel tests

The original workflow explicitly installed pytest-xdist via pip install pytest-retry==1.6.3 pytest-xdist google-genai==1.22.0 .... This PR removed pytest-xdist from the pip install line (along with pytest-retry), but pytest-xdist is not declared in pyproject.toml and is not in poetry.lock as a direct dependency.

Without pytest-xdist, the -n ${{ matrix.test-group.workers }} flag on line 106 will cause pytest to fail with an unrecognized option error, breaking all 10 test matrix jobs.

Suggested change

	poetry run pip install google-genai==1.22.0 \
	google-cloud-aiplatform>=1.38 fastapi-offline==1.7.3 python-multipart==0.0.22 openapi-core
	poetry run pip install google-genai==1.22.0 pytest-xdist \
	google-cloud-aiplatform>=1.38 fastapi-offline==1.7.3 python-multipart==0.0.22 openapi-core

[greptile-apps]

Additional Comments (1)

pyproject.toml
pytest-retry still active with retries = 20

pytest-retry remains as a dev dependency here and its configuration (retries = 20, retry_delay = 5 on lines 196-197) is still active in [tool.pytest.ini_options]. Since pytest-rerunfailures was added on line 169 and the workflow now passes --reruns, both retry plugins will be active simultaneously. A failing test will be retried up to 20 times by pytest-retry first, then re-run 2-3 additional times by pytest-rerunfailures — potentially executing a broken test 60+ times.

Either remove pytest-retry from here along with the retries/retry_delay config from [tool.pytest.ini_options], or remove pytest-rerunfailures and rely solely on pytest-retry.

[jquinter]

@greptile-apps review again

[greptile-apps]

Greptile Summary

This PR improves CI test stability by reducing pytest-xdist parallelism from 4 to 2 workers, adding pytest-rerunfailures for automatic test retries (2-3 reruns depending on test group), and increasing the job timeout from 15 to 20 minutes. It also includes a small fix replacing deprecated asyncio.iscoroutinefunction() with inspect.iscoroutinefunction() in logging_utils.py.

• Reduced parallel workers (4 → 2) across most test groups to mitigate race conditions from module reloading
• Added pytest-rerunfailures v14.0 as a dev dependency with per-group --reruns configuration
• Removed pytest-retry config (retries=20, retry_delay=5) but left pytest-retry itself as a dependency — both retry plugins will still be installed simultaneously
• The logging_utils.py change is correct but unrelated to the CI stability goal of this PR

Confidence Score: 3/5

• Low risk to production code; the only runtime change is a straightforward deprecation fix. CI config changes could have unintended interactions from having both retry plugins installed.
• The CI workflow changes are reasonable in intent but leave both pytest-retry and pytest-rerunfailures installed as dependencies, which can cause plugin interference. The logging_utils.py fix is correct. Previous review feedback was partially addressed (pytest-xdist restored, retry config removed) but the pytest-retry dependency cleanup was not completed.
• Pay close attention to pyproject.toml — pytest-retry should be removed to avoid two conflicting retry plugins being installed simultaneously.

Important Files Changed

Filename	Overview
.github/workflows/test-litellm-matrix.yml	Reduces parallel workers from 4 to 2, adds --reruns with pytest-rerunfailures, increases timeout to 20 min. Previous review issues (missing pytest-xdist, duplicate retry plugins) were partially addressed in follow-up commits.
litellm/litellm_core_utils/logging_utils.py	Replaces deprecated asyncio.iscoroutinefunction() with inspect.iscoroutinefunction() — a correct and low-risk fix. Unrelated to the CI changes in this PR.
pyproject.toml	Adds pytest-rerunfailures and removes retry config (retries=20, retry_delay=5), but leaves pytest-retry as a dependency — both plugins will be installed simultaneously, which can cause interference.
poetry.lock	Lock file updated to include pytest-rerunfailures v14.0. Content hash updated accordingly.

Flowchart

flowchart TD
    A[PR Trigger] --> B[Matrix Strategy: 10 test groups]
    B --> C[Install Dependencies]
    C --> D[poetry install]
    C --> E[pip install pytest-xdist, etc.]
    D --> F[pytest-retry installed via pyproject.toml]
    D --> G[pytest-rerunfailures installed via pyproject.toml]
    E --> H[Run Tests]
    H --> I[pytest -n 2 workers]
    I --> J{Test passes?}
    J -->|Yes| K[Mark passed]
    J -->|No| L[pytest-rerunfailures retries up to 2-3x]
    L --> M{Passes on rerun?}
    M -->|Yes| K
    M -->|No| N[Mark failed]
    N --> O{maxfail=10 reached?}
    O -->|Yes| P[Abort run]
    O -->|No| I

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[greptile-apps]

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[greptile-apps]

Additional Comments (1)

pyproject.toml
pytest-retry dependency should be removed

The config options (retries = 20, retry_delay = 5) were removed to address the duplicate retry concern, but the pytest-retry package itself is still declared as a dev dependency. Since the CI workflow now exclusively uses pytest-rerunfailures with --reruns, keeping pytest-retry installed is unnecessary. Even without explicit configuration, pytest-retry will still register its pytest plugin and could interfere with pytest-rerunfailures (e.g., both plugins hook into test outcome reporting). Removing the dependency avoids any silent interaction between the two plugins.

[jquinter]

@greptile-apps review again

[greptile-apps]

Greptile Summary

This PR improves CI test stability by reducing pytest-xdist parallelism from 4 to 2 workers, adding pytest-rerunfailures for automatic retries of flaky tests, increasing the job timeout from 15 to 20 minutes, and replacing the deprecated asyncio.iscoroutinefunction with inspect.iscoroutinefunction in logging_utils.py.

• Retry plugin consolidation: Cleanly replaces pytest-retry (with its aggressive retries=20) with pytest-rerunfailures using reasonable per-group --reruns values (1-3). The old retries/retry_delay ini_options are correctly removed.
• Dependency management improvement: Moves pytest-xdist from an ad-hoc pip install in the workflow to a declared dev dependency in pyproject.toml, which is a cleaner approach.
• Minor cleanup needed: pytest-retry entry is still present in poetry.lock as a stale orphan — running poetry lock --no-update would clean this up.
• Incomplete deprecation fix: The asyncio.iscoroutinefunction → inspect.iscoroutinefunction change in logging_utils.py is correct but the same deprecated API is used in 6 other files across the codebase.
• No evidence of impact: The PR claims to reduce failure rate from 80% to 10-20%, but no CI run results are provided to validate this claim.

Confidence Score: 3/5

• This PR is low-risk — CI configuration and a minor deprecation fix with no production logic changes.
• Score of 3 reflects that the changes are structurally sound (correct plugin swap, reasonable retry values, proper dep management), but the poetry.lock still contains a stale pytest-retry entry, the deprecation fix is incomplete across the codebase, and the claimed CI improvement lacks supporting evidence.
• Pay attention to poetry.lock (stale pytest-retry entry) and verify CI runs pass with the new configuration before merging.

Important Files Changed

Filename	Overview
.github/workflows/test-litellm-matrix.yml	Reduces parallelism from 4 to 2 workers, adds pytest-rerunfailures retry logic, increases timeout to 20min, and moves pytest-xdist/pytest-rerunfailures to pyproject.toml dev deps. Stale pytest-retry entry remains in poetry.lock. Tests marked no_parallel are still run in parallel (pre-existing issue).
litellm/litellm_core_utils/logging_utils.py	Replaces deprecated asyncio.iscoroutinefunction with inspect.iscoroutinefunction. Correct fix — asyncio.iscoroutinefunction is deprecated since Python 3.12.
pyproject.toml	Replaces pytest-retry with pytest-xdist in dev dependencies, adds pytest-rerunfailures, removes old retries=20/retry_delay=5 config. Clean transition to a single retry plugin.
poetry.lock	Adds pytest-rerunfailures 14.0 entry. However, pytest-retry 1.7.0 entry is still present as a stale orphan (no longer referenced in pyproject.toml).

Flowchart

flowchart TD
    A[PR Trigger] --> B[Matrix: 10 test groups]
    B --> C{Install Dependencies}
    C --> D[poetry install dev,proxy-dev]
    D --> E[pip install extra packages]
    E --> F[Setup litellm-enterprise]
    F --> G[Run pytest]
    G --> H{"-n 2 workers<br/>pytest-xdist"}
    H --> I[Test passes]
    H --> J[Test fails]
    J --> K{"--reruns 1-3<br/>pytest-rerunfailures"}
    K --> L[Retry passes]
    K --> M[Retry fails]
    M --> N{"--maxfail=10<br/>reached?"}
    N -->|Yes| O[Job fails]
    N -->|No| H
    I --> P[Job succeeds]
    L --> P

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[greptile-apps]

Additional Comments (1)

poetry.lock
Stale pytest-retry entry in lock file

pytest-retry was removed from pyproject.toml (replaced by pytest-xdist), but its entry still remains in poetry.lock. While Poetry should not install it (since it's no longer a declared dependency), this is a stale orphan entry that will cause the lock file content hash to be inconsistent. Running poetry lock should clean this up.

poetry lock --no-update