test(lsp): add tests for diagnostics on didOpen|didChange|didSave

[Sysix]

This PR adds comprehensive test coverage for diagnostic functionality in the Language Server Protocol (LSP) implementation, specifically testing diagnostics on didOpen, didChange, and didSave events. The changes include both unit tests for the worker module and integration tests for the backend

along with a bug fix in the did_save handler.

This is not really a bug fix, just a little refactoring to pass the tests.
In general, I do not expect that params.text (didSave) has changed from didChange content

[Sysix]

• fix(lsp): shutdown a WorkspaceWorker will clear diagnostics for all known files #16467
• perf(lsp): avoid Uri to String and back to Uri conversion #16470
• perf(lsp): avoid cloning when revalidating diagnostics #16469
• fix(oxlint/lsp): revalidate all known files after internal restart #16407
• test(lsp): add tests for diagnostics on didOpen|didChange|didSave #16466 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

This PR adds comprehensive test coverage for diagnostic functionality in the Language Server Protocol (LSP) implementation, specifically testing diagnostics on didOpen, didChange, and didSave events. The changes include both unit tests for the worker module and integration tests for the backend, along with a bug fix in the did_save handler.

Key Changes

• Added unit tests for run_diagnostic, run_diagnostic_on_change, and run_diagnostic_on_save methods in the worker module
• Added integration tests verifying diagnostic publishing on didOpen, didChange, and didSave LSP events
• Fixed bug in did_save handler to pass actual text content instead of None when available

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
crates/oxc_language_server/src/worker.rs	Added three unit tests (test_run_diagnostic, test_run_diagnostic_on_change, test_run_diagnostic_on_save) that verify the diagnostic collection methods work correctly with and without content
crates/oxc_language_server/src/tests.rs	Added three FakeTool methods for diagnostic testing and three integration tests (test_diagnostic_on_open, test_diagnostic_on_change, test_no_diagnostic_on_save) that verify end-to-end diagnostic publishing behavior
crates/oxc_language_server/src/backend.rs	Fixed did_save handler to pass params.text.as_deref() instead of None, ensuring saved file content is available for diagnostics

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[camc314]

Merge activity

• Dec 3, 10:27 PM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Dec 3, 10:27 PM UTC: camc314 added this pull request to the Graphite merge queue.
• Dec 3, 10:32 PM UTC: Merged by the Graphite merge queue.