feat(auth): consolidate multi-user auth and admin controls

backend/src/__tests__/testUtils.ts

@@ -2,11 +2,53 @@
  * Test utilities for backend integration tests
  */
 import { PrismaClient } from "../generated/client";
+import fs from "fs";
 import path from "path";
 import { execSync } from "child_process";
 
-// Use a separate test database
-const TEST_DB_PATH = path.resolve(__dirname, "../../prisma/test.db");
+// Use a unique test database per test-file import to avoid cross-file contention
+// when Vitest runs test files in parallel.
+const TEST_DB_FILENAME = `test.${process.pid}.${Math.random().toString(16).slice(2)}.db`;
+const TEST_DB_PATH = path.resolve(__dirname, "../../prisma", TEST_DB_FILENAME);
+const DB_PUSH_LOCK_PATH = path.resolve(__dirname, "../../prisma/.test-db-push.lock");
+
+const sleepSync = (ms: number) => {
+  const shared = new Int32Array(new SharedArrayBuffer(4));
+  Atomics.wait(shared, 0, 0, ms);
+};
+
+const withDbPushLock = (fn: () => void) => {
+  const start = Date.now();
+  let fd: number | null = null;
+  while (fd === null) {
+    try {
+      fd = fs.openSync(DB_PUSH_LOCK_PATH, "wx");
+      fs.writeFileSync(fd, String(process.pid));
+    } catch (error) {
+      const err = error as NodeJS.ErrnoException;
+      if (err.code !== "EEXIST") throw error;
+      if (Date.now() - start > 30_000) {
+        throw new Error("Timed out waiting for Prisma db push lock");
+      }
+      sleepSync(50);
+    }
+  }
+
+  try {
+    fn();
+  } finally {
+    try {
+      fs.closeSync(fd);
+    } catch {
+      // ignore
+    }
+    try {
+      fs.unlinkSync(DB_PUSH_LOCK_PATH);
+    } catch {
+      // ignore
+    }
+  }
+};
 
 /**
  * Get a test Prisma client pointing to the test database
@@ -32,10 +74,19 @@ export const setupTestDb = () => {
   
   // Run Prisma migrations to create the test database
   try {
-    execSync("npx prisma db push --skip-generate", {
-      cwd: path.resolve(__dirname, "../../"),
-      env: { ...process.env, DATABASE_URL: databaseUrl },
-      stdio: "pipe",
+    withDbPushLock(() => {
+      execSync("npx prisma db push --skip-generate --force-reset", {
+        cwd: path.resolve(__dirname, "../../"),
+        env: {
+          ...process.env,
+          DATABASE_URL: databaseUrl,
+          // Work around Prisma schema engine failures on this repo's schema
+          // (seen as a blank "Schema engine error:" from `prisma db push`).
+          // `RUST_LOG=info` reliably avoids the failure mode.
+          RUST_LOG: "info",
+        },
+        stdio: "pipe",
+      });
     });
   } catch (error) {
     console.error("Failed to setup test database:", error);