refactor: move tests to separate files

[nyurik]

tests became a bit hard to manage, so moving them into separate files. The integration tests were easy to move into tests/ dir, but the unit tests should be in a separate file because we don't want to grow public API surface

[Copilot]

Pull Request Overview

This PR reorganizes the test suite by moving integration tests from the main library module to separate test files. Unit tests that exercise private parser functions are moved to a new src/parser_tests.rs module file, while integration tests that use the public API are relocated to tests/parsing.rs. This refactoring improves code maintainability without expanding the public API surface.

Key changes:

• Created tests/parsing.rs for integration tests using public API
• Created src/parser_tests.rs for unit tests of internal parser functions
• Made several parser functions pub(crate) to enable internal testing
• Made ValDescription struct fields public to support integration test assertions

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
tests/parsing.rs	New integration test file containing tests that use the public Dbc API
src/parser_tests.rs	New unit test module containing parser function tests
src/lib.rs	Removed test module, added parser_tests module import, made ValDescription fields public
src/parser.rs	Removed inline test module, changed several parser functions from private to pub(crate) visibility

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[Copilot]

The XOR operator ^ is being used where bitwise OR | is likely intended. 2 ^ 29 evaluates to 31, not a 29-bit shifted value. This should be 2 | (1 << 29) or 2 + (1 << 29) if setting bit 29.

Suggested change

	let message_id = MessageId::Extended(2 ^ 29);
	assert_eq!(message_id.raw(), 2 ^ 29 | 1 << 31);
	let message_id = MessageId::Extended(2 | 1 << 29);
	assert_eq!(message_id.raw(), (2 | 1 << 29) | 1 << 31);

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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