test: move backend unit tests

[pvijayakrish]

Overview:

Move the backend unit tests for vLLM, SGLang, and TRTLLM into their respective backend subdirectories to align with the test directory structure.

Summary by CodeRabbit

• Tests

  • Reorganized Prometheus utility tests into backend-specific test modules for improved maintainability.
  • Added unit tests for Prometheus utilities across multiple backends with comprehensive filtering and error-handling validation.
  • Enhanced test configuration with improved fixture management and conditional test collection based on installed dependencies.

• Chores

  • Updated test path resolution to use repository-root anchoring for consistency across test suites.

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[coderabbitai]

Walkthrough

Tests for Prometheus utilities were moved from a centralized tests/unit/ module into backend-specific test directories; new backend conftest fixtures were added and unit tests updated to use repository-root-based path resolution.

Changes

Cohort / File(s)	Summary
Backend conftest factories & hooks components/src/dynamo/vllm/tests/conftest.py, components/src/dynamo/trtllm/tests/conftest.py	Add pytest_ignore_collect to skip backend tests when framework modules are absent and add make_cli_args_fixture(module_name: str) to produce a mock_cli_args fixture for mocking CLI argv (positional and kwargs styles).
Prometheus utils tests (per-backend) components/src/dynamo/vllm/tests/test_vllm_prometheus_utils.py, components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py, components/src/dynamo/trtllm/tests/test_trtllm_prometheus_utils.py	New backend-specific tests for get_prometheus_expfmt: fixtures mocking generate_latest, tests for metric prefix filtering/exclusion, prefix addition, HELP/TYPE preservation, label/value checks, empty-result handling, and error handling.
Backend unit test path & fixture updates components/src/dynamo/vllm/tests/test_vllm_unit.py, components/src/dynamo/sglang/tests/test_sglang_unit.py, components/src/dynamo/trtllm/tests/test_trtllm_unit.py	Update imports to use backend conftest make_cli_args_fixture; introduce REPO_ROOT and compute TEST_DIR/JINJA_TEMPLATE_PATH from repository root instead of relative file paths.
Removed centralized tests tests/unit/test_prometheus_utils.py	Remove the centralized Prometheus utilities test module (its fixtures and TestGetPrometheusExpfmt class were deleted in favor of backend-specific copies).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

• Areas to review closely:
  • correctness of pytest_ignore_collect patterns and their mapping to required module import checks;
  • parity between removed centralized tests and the new backend-specific test implementations (coverage and assertions);
  • REPO_ROOT calculation and resulting JINJA_TEMPLATE_PATH resolution across environments.

Poem

🐇 I hopped through tests and moved each little file,

Prometheus metrics found a cozy backend style.
Conftests stitched the argv, paths now rooted true,
Tiny rabbit cheers — the tests ran anew! 🥕

Pre-merge checks

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description Check	⚠️ Warning	The pull request description provides only the Overview section with a brief statement about moving backend unit tests into their respective subdirectories. However, the required template includes four key sections: Overview, Details, Where should the reviewer start, and Related Issues. The description lacks the Details section describing the specific changes made, guidance on where reviewers should focus, and any issue references. This represents incomplete coverage of the template structure, providing only approximately 25% of the expected content sections.
Docstring Coverage	⚠️ Warning	Docstring coverage is 73.91% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title "test: move backend unit tests" directly and concisely describes the primary change in the pull request. The changeset moves unit tests for vLLM, SGLang, and TRTLLM backends into their respective backend subdirectories, which is accurately captured by the title. The title uses conventional commit formatting with a "test:" prefix and is specific and clear enough for someone scanning history to understand the primary change without ambiguity.

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

components/src/dynamo/trtllm/tests/conftest.py (1)

16-77: Consider consolidating duplicate conftest code across backends.

The pytest_ignore_collect and make_cli_args_fixture implementations are identical across all three backend conftest files (vllm, sglang, trtllm). Consider extracting these into a shared test utilities module to reduce duplication.

📜 Review details

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 1da9d70 and 38f618a.

📒 Files selected for processing (9)

• components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py (1 hunks)
• components/src/dynamo/sglang/tests/test_sglang_unit.py (1 hunks)
• components/src/dynamo/trtllm/tests/conftest.py (1 hunks)
• components/src/dynamo/trtllm/tests/test_trtllm_prometheus_utils.py (1 hunks)
• components/src/dynamo/trtllm/tests/test_trtllm_unit.py (1 hunks)
• components/src/dynamo/vllm/tests/conftest.py (1 hunks)
• components/src/dynamo/vllm/tests/test_vllm_prometheus_utils.py (1 hunks)
• components/src/dynamo/vllm/tests/test_vllm_unit.py (1 hunks)
• tests/unit/test_prometheus_utils.py (0 hunks)

💤 Files with no reviewable changes (1)

• tests/unit/test_prometheus_utils.py

🧰 Additional context used

🧠 Learnings (2)

📓 Common learnings

Learnt from: nnshah1
PR: ai-dynamo/dynamo#1444
File: tests/fault_tolerance/scenarios.py:57-57
Timestamp: 2025-07-01T15:39:56.789Z
Learning: The fault tolerance tests in tests/fault_tolerance/ are designed to run only in the mounted container environment, so hardcoded absolute paths with `/workspace/` prefix are intentional and should not be changed to relative paths.

📚 Learning: 2025-07-01T15:39:56.789Z

Learnt from: nnshah1
PR: ai-dynamo/dynamo#1444
File: tests/fault_tolerance/scenarios.py:57-57
Timestamp: 2025-07-01T15:39:56.789Z
Learning: The fault tolerance tests in tests/fault_tolerance/ are designed to run only in the mounted container environment, so hardcoded absolute paths with `/workspace/` prefix are intentional and should not be changed to relative paths.

Applied to files:

• components/src/dynamo/trtllm/tests/test_trtllm_unit.py

🧬 Code graph analysis (6)

components/src/dynamo/vllm/tests/test_vllm_prometheus_utils.py (2)

components/src/dynamo/common/utils/prometheus.py (1)

• get_prometheus_expfmt (100-197)

components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py (4)

• TestGetPrometheusExpfmt (17-98)
• mock_generate_latest (42-43)
• mock_generate_latest (54-55)
• test_error_handling (89-98)

components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py (1)

components/src/dynamo/common/utils/prometheus.py (1)

• get_prometheus_expfmt (100-197)

components/src/dynamo/trtllm/tests/test_trtllm_prometheus_utils.py (1)

components/src/dynamo/common/utils/prometheus.py (1)

• get_prometheus_expfmt (100-197)

components/src/dynamo/trtllm/tests/test_trtllm_unit.py (1)

components/src/dynamo/trtllm/tests/conftest.py (1)

• make_cli_args_fixture (38-77)

components/src/dynamo/vllm/tests/test_vllm_unit.py (1)

components/src/dynamo/vllm/tests/conftest.py (1)

• make_cli_args_fixture (38-77)

components/src/dynamo/sglang/tests/test_sglang_unit.py (1)

components/src/dynamo/sglang/tests/conftest.py (1)

• make_cli_args_fixture (38-77)

🪛 Ruff (0.14.2)

components/src/dynamo/vllm/tests/test_vllm_prometheus_utils.py

40-40: Unused function argument: reg

(ARG001)

components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py

42-42: Unused function argument: reg

(ARG001)

---

54-54: Unused function argument: reg

(ARG001)

components/src/dynamo/trtllm/tests/test_trtllm_prometheus_utils.py

43-43: Unused function argument: reg

(ARG001)

components/src/dynamo/vllm/tests/conftest.py

16-16: Unused function argument: config

(ARG001)

components/src/dynamo/trtllm/tests/conftest.py

16-16: Unused function argument: config

(ARG001)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (1)

• GitHub Check: Build and Test - dynamo

🔇 Additional comments (8)

components/src/dynamo/sglang/tests/test_sglang_unit.py (1)

13-21: LGTM! Test infrastructure updated correctly for new location.

The import path change and REPO_ROOT-based path resolution properly support the test file's new location in the backend subdirectory.

components/src/dynamo/trtllm/tests/conftest.py (1)

16-35: LGTM! The pytest hook signature is correct.

The config parameter is part of the standard pytest hook signature for pytest_ignore_collect and must be present even when unused.

components/src/dynamo/trtllm/tests/test_trtllm_unit.py (1)

11-20: LGTM! Test infrastructure correctly updated.

The import path and REPO_ROOT-based path resolution are properly configured for the test file's new backend-specific location.

components/src/dynamo/vllm/tests/conftest.py (1)

16-77: LGTM! Conftest utilities correctly implemented.

The conditional test collection hook and CLI args fixture factory provide proper test infrastructure for the vLLM backend.

components/src/dynamo/sglang/tests/test_sglang_prometheus_utils.py (1)

66-98: LGTM! Test cases properly validate Prometheus filtering.

The tests correctly verify metric filtering, exclusion, label preservation, and error handling for the SGLang backend.

components/src/dynamo/vllm/tests/test_vllm_prometheus_utils.py (1)

20-83: LGTM! Prometheus utility tests correctly implemented.

The fixture and test cases properly validate metric filtering, exclusion, and error handling for the vLLM backend.

components/src/dynamo/trtllm/tests/test_trtllm_prometheus_utils.py (1)

20-111: LGTM! Comprehensive Prometheus utility test coverage.

The fixture and test cases thoroughly validate metric filtering, prefix addition, default behavior, edge cases, and error handling for the TensorRT-LLM backend.

components/src/dynamo/vllm/tests/test_vllm_unit.py (1)

12-20: LGTM! Test infrastructure properly updated.

The import path and REPO_ROOT-based path resolution correctly support the test file's relocation to the vLLM backend subdirectory.

[pvijayakrish]

/ok to test 38f618a

[KrishnanPrash]

Left a few comments about cleaning up conftest.py

[pvijayakrish]

/ok to test d5d35a8

[pvijayakrish]

Changes LGTM. Thanks for help with refactoring. If you could, please test the unit tests for sglang locally because the container build is failing currently.

vllm, sglang and trtllm unit tests have been tested both in ci and locally.
example workflow run: https://github.com/ai-dynamo/dynamo/actions/runs/18979395716/job/54207758363?pr=3958

[pvijayakrish]

/ok to test f9a24c9