Handle jointless-articulation warnings in USD tests

[adenzler-nvidia]

Description

test_import_usd has several fixtures that intentionally import single-body (jointless) articulations. OpenUSD < 26.0 — the usd-exchange build resolved on aarch64 — reports an articulation root with no joints as an invalid ArticulationDesc, so parse_usd emits a UserWarning; usd-core >= 26.0 (every other platform) treats it as valid. Newton imports the body identically either way, so these tests pass today, but they fail on aarch64 only once the suite escalates newton.* warnings to errors (the upcoming --strict-warnings mode in #3044).

Changes:

• Drop the unnecessary ArticulationRootAPI from the parsing fixtures that only used it as scaffolding around a single body (material / contact response / gap / margin / solref / mujoco-options). They do not test articulations.
• For the composition and parent-offset fixtures, where the articulation is the behavior under test, assert exactly the expected warning on OpenUSD < 26.0 (scoped by Usd.GetVersion()), while leaving every other warning subject to the ambient policy so an unexpected newton.* warning still fails under strict mode.
• Tighten test_contact_response_legacy_shape_fallback: replace the blanket simplefilter("always"), which masked every warning, with a DeprecationWarning-scoped filter, and exact-match the per-attribute migration messages instead of substring-matching.

This is preparatory cleanup with no behavior change on main (the warning is non-fatal without --strict-warnings), so #3044 can go green on aarch64.

Checklist

• New or existing tests cover these changes
• The documentation is up to date with these changes
• CHANGELOG.md has been updated (if user-facing change) — not applicable, test-only

Test plan

Verified on both USD builds by simulating #3044's strict filters (filterwarnings("error", category=DeprecationWarning) and filterwarnings("error", module=r"newton(\.|$)")): on usd-core 26.0+ the affected tests pass and the _expect_* decorator is a no-op; on the usd-exchange (OpenUSD 25.5) build the parsing fixtures emit no warning, the decorated fixtures record and assert exactly the expected warning, and an unrelated warning still escalates.

uv run --extra dev -m newton.tests -k SampleAssets
uv run --extra dev -m newton.tests -k test_import_articulation_parent_offset

Summary by CodeRabbit

• Tests
  • Updated test suite to handle OpenUSD version compatibility warnings (versions older than 26.0).
  • Refactored physics articulation tests to properly manage deprecation warnings with stricter validation.
  • Added helper mechanisms for version-specific warning handling in test infrastructure.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR updates newton/tests/test_import_usd.py to handle OpenUSD 26.0 compatibility by introducing a version-gated warning decorator for jointless articulations and adjusting test fixtures to either suppress or avoid the warning, alongside tightening deprecation warning assertions in legacy contact-response tests.

Changes

USD Warning and Articulation Handling

Layer / File(s)	Summary
Version-gated jointless-articulation warning decorator newton/tests/test_import_usd.py	New _expect_jointless_articulation_warning decorator conditionally captures and asserts a specific OpenUSD "invalid articulation desc" UserWarning when USD version < 26.0. The decorator is applied to eight tests that create jointless articulations: test_import_articulation_parent_offset, test_parent_body_attaches_to_existing_body, test_parent_body_with_base_joint_creates_d6, test_parent_body_creates_joint_to_parent, test_floating_true_with_parent_body_raises_error, test_floating_false_with_parent_body_succeeds, test_non_sequential_articulation_attachment, and test_three_level_hierarchical_composition.
ArticulationRootAPI removal and deprecation assertion tightening newton/tests/test_import_usd.py	Eight test fixtures are modified to remove ArticulationRootAPI application and define their articulation setup as plain UsdGeom.Xform instead: test_parse_mujoco_options_disabled, test_material_parsing, test_contact_margin_parsing, test_contact_gap_parsing, test_contact_response_parsing, test_contact_response_inf_sentinel, test_contact_response_legacy_shape_fallback, and test_contact_response_solref_over_material. Additionally, test_contact_response_legacy_shape_fallback replaces broad warnings.simplefilter("always") with explicit warnings.filterwarnings("always", category=DeprecationWarning) and replaces loose substring-based checks with exact-message assertions counting each expected migration message to appear exactly twice.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• newton-physics/newton#3005: Both PRs update deprecation warning expectations in test_contact_response_legacy_shape_fallback for Newton's deprecated per-shape newton:contact_ke/contact_kd handling.

Suggested labels

usd

Suggested reviewers

• vreutskyy

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: handling jointless-articulation warnings in USD tests, which is the core focus of the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

🧹 Nitpick comments (1)

newton/tests/test_import_usd.py (1)

38-39: ⚡ Quick win

Avoid a Sphinx :func: link to private parse_usd.

Line 38 references :func:\~newton.utils.parse_usd`, but parse_usd is a private helper and not a stable public Sphinx target. Prefer inline code (``parse_usd()``) or reference the public entry point (ModelBuilder.add_usd`).

Based on learnings: parse_usd in newton/_src/utils/import_usd.py is private and should not be referenced via Sphinx :func: targets; use inline code literals instead. As per coding guidelines, use Sphinx cross-references against public API paths.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@newton/tests/test_import_usd.py` around lines 38 - 39, Replace the Sphinx
:func: cross-reference to the private helper parse_usd with an inline code
literal or a public API reference: change ":func:`~newton.utils.parse_usd`" to
"``parse_usd()``" or to the public entry point ":meth:`ModelBuilder.add_usd`" so
the docs do not point to the private function parse_usd (the helper in
import_usd.py) and instead reference a stable public target.

Sources: Coding guidelines, Learnings

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@newton/tests/test_import_usd.py`:
- Around line 38-39: Replace the Sphinx :func: cross-reference to the private
helper parse_usd with an inline code literal or a public API reference: change
":func:`~newton.utils.parse_usd`" to "``parse_usd()``" or to the public entry
point ":meth:`ModelBuilder.add_usd`" so the docs do not point to the private
function parse_usd (the helper in import_usd.py) and instead reference a stable
public target.

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📥 Commits

Reviewing files that changed from the base of the PR and between 839284a and 17e7bcb.

📒 Files selected for processing (1)

• newton/tests/test_import_usd.py

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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