import { defineConfig } from "vitest/config";
import path from "node:path";

export default defineConfig({
  resolve: {
    alias: {
      "@": path.resolve(__dirname, "./src"),
    },
  },
  test: {
    environment: "node",
    setupFiles: ["./tests/setup.ts"],
    // Each test file spins up its own throwaway Postgres database by
    // mutating process.env.DATABASE_URL in tests/setup.ts's beforeAll (see
    // that file). That per-file DB switch is not safe under Vitest's default
    // parallel file execution: two files' beforeAll/query timing can
    // interleave such that both end up issuing real queries against the
    // same throwaway DB (confirmed empirically once Request gained a real
    // FK to Employee — tests/employees.test.ts and tests/requests.test.ts
    // started intermittently deleting/reading each other's rows, causing
    // spurious FK-violation and row-count failures that disappear when run
    // sequentially). Disabling file parallelism trades a bit of wall-clock
    // test time for correctness — each file's throwaway DB is now genuinely
    // private for the duration of that file's run.
    fileParallelism: false,
  },
});