diff --git a/web/package.json b/web/package.json
index 3ee904a..6a94c27 100644
--- a/web/package.json
+++ b/web/package.json
@@ -6,7 +6,7 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "test": "vitest run",
+    "test": "DATABASE_URL=postgresql://lyra:lyra@localhost:5432/lyra_test vitest run",
     "postinstall": "prisma generate",
     "db:migrate": "prisma migrate deploy",
     "db:dev": "prisma migrate dev"
diff --git a/web/src/test/setup.ts b/web/src/test/setup.ts
index 5d0b12e..d4bb9b1 100644
--- a/web/src/test/setup.ts
+++ b/web/src/test/setup.ts
@@ -2,6 +2,13 @@ import { beforeEach } from "vitest";
 import { prisma } from "@/lib/db";
 
 beforeEach(async () => {
+  const dbName = (process.env.DATABASE_URL ?? "").split("/").pop()?.split("?")[0] ?? "";
+  if (!dbName.endsWith("_test")) {
+    throw new Error(
+      `refusing to run test cleanup against non-test database '${dbName}'. ` +
+      "Set DATABASE_URL to a database whose name ends in '_test' (e.g. lyra_test).",
+    );
+  }
   // Job cascades from Request; Request.monitoredReleaseId is SetNull. Delete children first.
   await prisma.job.deleteMany();
   await prisma.request.deleteMany();
diff --git a/worker/tests/conftest.py b/worker/tests/conftest.py
index e7a7fb0..db298f3 100644
--- a/worker/tests/conftest.py
+++ b/worker/tests/conftest.py
@@ -1,12 +1,24 @@
 import os
 
+os.environ.setdefault("DATABASE_URL", "postgresql://lyra:lyra@localhost:5432/lyra_test")
+
 import psycopg
 import pytest
 
 
+def _require_test_db(dsn: str) -> None:
+    name = dsn.rsplit("/", 1)[-1].split("?")[0]
+    if not name.endswith("_test"):
+        raise RuntimeError(
+            f"refusing to run destructive test fixtures against non-test database '{name}'. "
+            "Point DATABASE_URL at a database whose name ends in '_test' (e.g. lyra_test)."
+        )
+
+
 @pytest.fixture()
 def conn():
     dsn = os.environ["DATABASE_URL"]
+    _require_test_db(dsn)
     connection = psycopg.connect(dsn)
     # Clean up any pre-existing rows before the test runs (Job cascades from Request).
     with connection.cursor() as cur: