vitest/test/e2e/project-references/packages/project-b/tsconfig.json

{
  "compilerOptions": {
    "composite": true,
    "target": "esnext",
    "lib": ["DOM", "ESNext"],
    "module": "nodenext",
    "types": [],
    "strict": true,
    "declaration": true,
    "declarationMap": true,
    "outDir": "dist",
    "sourceMap": true,
    "verbatimModuleSyntax": true,
    "skipLibCheck": false
  },
  "references": [
    { "path": "../project-a" }
  ],
  "files": ["src/b.test-d.ts"],
  "exclude": ["node_modules"]
}