Revert "remove old tests"

This reverts commit 258e447.

test/unit/web-runtime/next-response.test.ts

@@ -4,6 +4,47 @@
 
 import { NextResponse } from 'next/server/web/spec-extension/response'
 
+const toJSON = async (response) => ({
+  body: await response.json(),
+  contentType: response.headers.get('content-type'),
+  status: response.status,
+})
+
+it('automatically parses and formats JSON', async () => {
+  expect(await toJSON(NextResponse.json({ message: 'hello!' }))).toMatchObject({
+    contentType: 'application/json',
+    body: { message: 'hello!' },
+  })
+
+  expect(
+    await toJSON(NextResponse.json({ status: 'success' }, { status: 201 }))
+  ).toMatchObject({
+    contentType: 'application/json',
+    body: { status: 'success' },
+    status: 201,
+  })
+
+  expect(
+    await toJSON(
+      NextResponse.json({ error: { code: 'bad_request' } }, { status: 400 })
+    )
+  ).toMatchObject({
+    contentType: 'application/json',
+    body: { error: { code: 'bad_request' } },
+    status: 400,
+  })
+
+  expect(await toJSON(NextResponse.json(null))).toMatchObject({
+    contentType: 'application/json',
+    body: null,
+  })
+
+  expect(await toJSON(NextResponse.json(''))).toMatchObject({
+    contentType: 'application/json',
+    body: '',
+  })
+})
+
 it('can be cloned', async () => {
   const fetchResponse = await fetch('https://example.vercel.sh')
   const newResponse = new NextResponse(fetchResponse.body, fetchResponse)