test(client): port too many instances (#13927)

* test: port too many instances

* refactor: use jest.resetModules

* delete: old test

packages/client/tests/functional/too-many-instances-of-prisma-client/_matrix.ts

@@ -0,0 +1,24 @@
+import { defineMatrix } from '../_utils/defineMatrix'
+
+export default defineMatrix(() => [
+  [
+    {
+      provider: 'sqlite',
+    },
+    {
+      provider: 'postgresql',
+    },
+    {
+      provider: 'mysql',
+    },
+    {
+      provider: 'sqlserver',
+    },
+    {
+      provider: 'cockroachdb',
+    },
+    {
+      provider: 'mongodb',
+    },
+  ],
+])

packages/client/tests/functional/too-many-instances-of-prisma-client/prisma/_schema.ts

@@ -0,0 +1,19 @@
+import { idForProvider } from '../../_utils/idForProvider'
+import testMatrix from '../_matrix'
+
+export default testMatrix.setupSchema(({ provider }) => {
+  return /* Prisma */ `
+    generator client {
+      provider = "prisma-client-js"
+    }
+    
+    datasource db {
+      provider = "${provider}"
+      url      = env("DATABASE_URI_${provider}")
+    }
+    
+    model User {
+      id ${idForProvider(provider)}
+    }
+  `
+})

packages/client/tests/functional/too-many-instances-of-prisma-client/tests.ts

@@ -0,0 +1,36 @@
+import testMatrix from './_matrix'
+
+// @ts-ignore this is just for type checks
+declare let PrismaClient: typeof import('@prisma/client').PrismaClient
+
+testMatrix.setupTestSuite(() => {
+  const oldConsoleWarn = console.warn
+  const warnings: any[] = []
+  const clients: any[] = []
+
+  beforeAll(() => {
+    jest.resetModules()
+
+    console.warn = (args) => {
+      warnings.push(args)
+    }
+  })
+
+  afterAll(() => {
+    console.warn = oldConsoleWarn
+  })
+
+  test('should console warn when spawning too many instances of PrismaClient', async () => {
+    for (let i = 0; i < 15; i++) {
+      const client = new PrismaClient()
+      await client.$connect()
+      clients.push(client)
+    }
+
+    for (const client of clients) {
+      client.$disconnect()
+    }
+
+    expect(warnings.join('')).toContain('There are already 10 instances of Prisma Client actively running')
+  })
+})