[derive] Refactor is_bit_valid tests

[joshlf]

---

• 　 [WIP] Remove MutationCompatible, Read #2878
• 　 [derive] Allow TryFromBytes on non-Immutable unions #2876
• 👉 [derive] Refactor is_bit_valid tests #2875
• 　 [WIP] Use ReadOnly in is_bit_valid #2873
• 　 [WIP] ReadOnly #2866
• 　 Make SizeEq safe, introduce CastExact #2872

Latest Update: v6 — Compare vs v5

📚 Full Patch History

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[gemini-code-assist]

Summary of Changes

Hello @joshlf, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request focuses on refactoring and streamlining the test suite for the is_bit_valid functionality within the zerocopy-derive crate. By introducing a dedicated helper function, the changes aim to consolidate redundant test setup logic, making the tests more concise, easier to understand, and simpler to maintain. The update improves the overall quality of the test code without altering the core behavior of the zerocopy library.

Highlights

• New Test Helper Function: A new public function, test_is_bit_valid, has been introduced in zerocopy-derive/tests/include.rs. This helper centralizes the common logic for testing TryFromBytes::is_bit_valid implementations, reducing boilerplate in individual test cases.
• Test Refactoring and Simplification: Numerous existing is_bit_valid tests across zerocopy-derive/tests/struct_try_from_bytes.rs and zerocopy-derive/tests/union_try_from_bytes.rs have been refactored to utilize the new test_is_bit_valid helper. This significantly reduces code duplication, removes complex Ptr manipulation, and improves the readability and maintainability of the test suite.
• Added IntoBytes Derive: The #[derive(imp::IntoBytes)] attribute has been added to several test structs and unions (e.g., One, Two, MaybeFromBytes) where necessary. This ensures they implement the IntoBytes trait, which is a requirement for the val argument of the new test_is_bit_valid helper function.
• Expanded Test Coverage: New valid and invalid test cases have been added for various types within the refactored tests, leveraging the simplified approach provided by the test_is_bit_valid helper. This includes additional checks for structs and unions with different field values and byte representations.

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[gemini-code-assist]

Code Review

This pull request provides an excellent refactoring of the is_bit_valid tests. The new test_is_bit_valid helper function significantly simplifies the test code in struct_try_from_bytes.rs and union_try_from_bytes.rs by abstracting away boilerplate for pointer manipulation and casting. This makes the tests much more concise, readable, and maintainable. The addition of the IntoBytes derive to various test types is appropriate and necessary for the new helper. The cleanup of the un_sized test, which can't use the new helper due to its DST nature, is also a good improvement. Overall, this is a high-quality change that improves the test suite.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.51%. Comparing base (6cbe1ca) to head (dd15299).

Additional details and impacted files

@@                            Coverage Diff                             @@
##           G7691845b6b02e9f3d9578435d732bacfa6ca674f    #2875   +/-   ##
==========================================================================
  Coverage                                      91.51%   91.51%           
==========================================================================
  Files                                             20       20           
  Lines                                           5919     5919           
==========================================================================
  Hits                                            5417     5417           
  Misses                                           502      502           

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[joshlf]

Superseded by #2879