chore: improve grpc-rs maintenance path

[vip892766gma]

Summary:

• Add unit tests for error conversion paths (RpcStatus -> Error, ShutdownFailed display formatting) and add explicit error branch coverage for edge cases in the error module that currently lack test coverage.
• Keep the change narrow so it is straightforward to review.

Notes:

• I kept this scoped to the relevant implementation and tests.

Summary by CodeRabbit

• Tests
  • Expanded error handling test coverage to ensure improved reliability.

[ti-chi-bot]

Welcome @vip892766gma! It looks like this is your first PR to tikv/grpc-rs 🎉

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• 4695d83 chore: improve grpc-rs maintenance path

Details

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[coderabbitai]

📝 Walkthrough

Walkthrough

Error test coverage is reorganized and expanded. A unified test module replaces protobuf-specific tests, adding Display formatting validation for multiple Error variants and source() assertion for non-codec errors, while retaining the protobuf conversion test behind a feature gate.

Changes

Error test coverage expansion

Layer / File(s)	Summary
Error Display and source() test coverage src/error.rs	New unified #[cfg(test)] module validates Display output for Error variants including RpcFailure with/without message, ShutdownFailed, and RpcFinished; asserts source() is None for non-codec cases; protobuf WireError conversion test moved behind #[cfg(feature = "protobuf-codec")] within this shared module.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

Poem

A rabbit hops through error tests so bright,
Display and source() now shine in the light,
Protobuf tucked behind its feature gate,
Test coverage grows—what a wonderful fate! 🐰✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The PR title 'chore: improve grpc-rs maintenance path' is vague and generic. While 'chore' correctly categorizes the change type, the phrase 'improve maintenance path' does not clearly describe what the actual change accomplishes—expanding test coverage in src/error.rs.	Consider a more specific title like 'chore: expand error module test coverage' or 'test: add unit tests for error conversions' to clearly communicate the primary change.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
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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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

🧹 Nitpick comments (1)

src/error.rs (1)

121-132: ⚡ Quick win

Consider adding source() assertion for consistency.

The other test functions verify that source() returns None for non-Codec errors. Consider adding similar assertions here for consistency:

         assert_eq!(
             err_some.to_string(),
             "RpcFinished(Some(RpcStatus { code: 1-CANCELLED, message: \"\", details: [], debug_error_string: \"\" }))"
         );
+        assert!(err_none.source().is_none());
+        assert!(err_some.source().is_none());

🤖 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 `@src/error.rs` around lines 121 - 132, Add a source() assertion to the
test_rpc_finished_display test to mirror other tests: after constructing
err_none and err_some (Error::RpcFinished(None) and
Error::RpcFinished(Some(...))) call their source() and assert it is None. Update
the test function test_rpc_finished_display to include these two assertions so
both non-Codec RpcFinished variants explicitly verify source() returns None.

🤖 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 `@src/error.rs`:
- Around line 121-132: Add a source() assertion to the test_rpc_finished_display
test to mirror other tests: after constructing err_none and err_some
(Error::RpcFinished(None) and Error::RpcFinished(Some(...))) call their source()
and assert it is None. Update the test function test_rpc_finished_display to
include these two assertions so both non-Codec RpcFinished variants explicitly
verify source() returns None.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 5299a8cc-761f-4bc4-b1d1-0cf2da4f6892

📥 Commits

Reviewing files that changed from the base of the PR and between edb4d96 and 4695d83.

📒 Files selected for processing (1)

• src/error.rs