test-writing

name	test-writing
description	Writes unit tests for vscode-deephaven using Vitest and TypeScript. Use when writing tests, adding unit tests for new features, or verifying service/component behavior. Covers test structure, mocking patterns, parameterized tests, and vscode-deephaven-specific conventions.

Test Writing for vscode-deephaven

Running Tests

Use npx vitest run for all test execution. Avoid npm test (starts watch mode).

# Run all tests
npx vitest run

# Run specific test file
npx vitest run src/path/to/file.spec.ts

# Run multiple specific files
npx vitest run src/mcp/tools/getColumnStats.spec.ts src/mcp/tools/getTableStats.spec.ts

Codebase-Specific Conventions

1. Shared VS Code Mocks

Always check __mocks__/vscode.ts before creating new mocks. Read the file to see what's available (e.g., Uri, EventEmitter, DiagnosticCollection, etc.).

vi.mock('vscode');

// Use shared mocks, don't recreate them
const diagnosticCollection = vscode.languages.createDiagnosticCollection();

2. Mock Specific Modules, Not Barrel Exports

// ✅ Specific module
vi.mock('../../services/DhcService', async () => {
   actual =  vi.();
   { ...actual, : vi.() };
});


vi.();