Add LSP server tests

[ultmaster]

Summary

• add VS Code LSP server test suite covering diagnostics, hover and completion

Testing

• npm test
• npm run test-vscode (fails: ENOENT or large output)

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https://chatgpt.com/codex/tasks/task_e_686242735268832e9463f9c2adbea89d

[cursor]

Bug: Completion Test Fails on Unexpected Return Types

The completion test (test('completion suggests attributes')) contains two related bugs:

1. The result of vscode.commands.executeCommand('vscode.executeCompletionItemProvider') is incorrectly assumed to be a CompletionList with an items property. If the command returns CompletionItem[] or null/undefined, accessing .items will cause a runtime error.
2. Within the mapping of completion item labels, item.label.label is accessed without ensuring item.label is an object with a label property, which can lead to a TypeError.

packages/poml-vscode/tests/lsp.test.ts#L91-L93

poml/packages/poml-vscode/tests/lsp.test.ts

Lines 91 to 93 in 8bd89bf

	const pos = new vscode.Position(0, doc.getText().length);
	const list = (await vscode.commands.executeCommand('vscode.executeCompletionItemProvider', doc.uri, pos)) as vscode.CompletionList;
	const labels = list.items.map(item => (typeof item.label === 'string' ? item.label : item.label.label));

Fix in Cursor

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Bug: Unprotected Array Access Causes TypeError

The code attempts to access hovers[0].contents[0] without verifying that hovers[0].contents exists or contains elements. This can lead to a TypeError if contents is undefined or an empty array, as the index access [0] will fail before the nullish coalescing operator can be applied.

packages/poml-vscode/tests/lsp.test.ts#L81-L82

poml/packages/poml-vscode/tests/lsp.test.ts

Lines 81 to 82 in 8bd89bf

	assert.ok(hovers && hovers.length > 0, 'No hover result');
	const text = (hovers[0].contents[0] as any).value ?? '';

Fix in Cursor

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[Copilot]

Pull Request Overview

This PR adds a VS Code LSP server test suite to validate diagnostics, hover, and completion functionality.

• Introduces new tests for LSP diagnostics, hover responses, and completions
• Includes tests to verify preview features and behavior with bad syntax files
• Adds teardown steps to close editors after tests to avoid interference between tests

Reviewed Changes

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

File	Description
packages/poml-vscode/tests/preview.test.ts	Added preview feature tests with improved teardown handling
packages/poml-vscode/tests/lsp.test.ts	New LSP server tests for diagnostics, hover, completion, preview
packages/poml-vscode/test-fixtures/badSyntaxLsp.poml	Fixture file with intentionally bad syntax for diagnostics

[Copilot]

Consider replacing this fixed delay with an event-based or promise-driven approach to ensure editors are fully closed before tests continue.

Suggested change

	await new Promise(resolve => setTimeout(resolve, 500));
	await new Promise(resolve => {
	const interval = setInterval(() => {
	if (vscode.workspace.textDocuments.length === 0) {
	clearInterval(interval);
	resolve();
	}
	}, 100);
	});

[Copilot]

Consider using event-based synchronization for the LSP server startup instead of relying on a fixed timeout, which may lead to flaky tests.

Suggested change

	await new Promise(resolve => setTimeout(resolve, 3000));
	await client.onReady();