Fix causal conv1d test collection with older cuDNN

[yeliu-oss]

What changed

• Resolve causal-conv1d test bindings lazily with getattr(cudnn, binding_name, None).
• Skip only parameter cases whose binding is absent from the frontend build.

Why

cuDNN builds older than 9.22 do not export these optional Python symbols. Referencing them directly in pytest parametrization raises AttributeError during module collection, before pytest can skip unsupported cases.

Binding presence is the source of truth here, so the test does not duplicate effective cuDNN backend-version logic already enforced by the binding layer.

Validation

Built the current frontend branch from source twice against matched headers and runtime libraries from official packages:

• nvidia-cudnn-cu13==9.22.0.52: cudnn.backend_version() == 92200; 16 passed
• nvidia-cudnn-cu13==9.24.0.43: cudnn.backend_version() == 92400; 16 passed
• black --check --line-length 160 --fast test/python/test_causal_conv1d.py
• git diff --check origin/develop..HEAD

Fixes #468

Summary by CodeRabbit

• Tests
  • Improved causal convolution compatibility checks across cuDNN frontend builds.
  • Test cases now skip unavailable bindings while continuing to validate unsupported kernel-size handling.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 073ce27 and 9a68611.

📒 Files selected for processing (1)

• test/python/test_causal_conv1d.py

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📝 Walkthrough

Walkthrough

Changes

Causal convolution test compatibility

Layer / File(s)	Summary
Dynamic binding resolution test/python/test_causal_conv1d.py	Parameterized cases now store binding names. The test resolves each binding with getattr and skips unavailable bindings while preserving unsupported kernel-size validation.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the fix for causal conv1d test collection with older cuDNN versions.
Description check	✅ Passed	The description explains the change, cause, compatibility impact, validation results, and linked issue; omitted template sections are non-critical.
Linked Issues check	✅ Passed	The lazy binding lookup and selective skipping directly resolve issue #468 by preventing collection failures on cuDNN versions without causal-conv1d bindings.
Out of Scope Changes check	✅ Passed	The changes are limited to the causal conv1d Python test and directly support the linked issue objective.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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