fix(email-resend): http fetch error handling swallows errors (#17798)

copy of #17795 for v3

Author: DanRibbens

packages/email-resend/src/email-resend.int.spec.ts

@@ -0,0 +1,52 @@
+import type { Payload } from 'payload'
+
+import { describe, expect, it } from 'vitest'
+
+import { resendAdapter } from './index.js'
+
+/**
+ * Real end-to-end checks against the live Resend API. Skipped unless RESEND_API_KEY
+ * is set, so the default unit run and CI never hit the network.
+ *
+ * Run with:
+ *   RESEND_API_KEY=re_xxx pnpm vitest run packages/email-resend/src/email-resend.int.spec.ts
+ *
+ * Uses Resend's sandbox identities, which require no domain verification:
+ *   from:  onboarding@resend.dev
+ *   to:    delivered@resend.dev  (also bounced@resend.dev / complained@resend.dev)
+ */
+describe.skipIf(!process.env.RESEND_API_KEY)('email-resend (integration)', () => {
+  const mockPayload = {} as unknown as Payload
+
+  const adapter = (apiKey: string) =>
+    resendAdapter({
+      apiKey,
+      defaultFromAddress: 'onboarding@resend.dev',
+      defaultFromName: 'Payload Integration Test',
+    })({ payload: mockPayload })
+
+  it('should send a real email and return a Resend id', async () => {
+    const result = (await adapter(process.env.RESEND_API_KEY!).sendEmail({
+      from: 'Payload <onboarding@resend.dev>',
+      subject: 'Payload email-resend integration test',
+      text: 'This message was sent by the email-resend integration test.',
+      to: 'delivered@resend.dev',
+    })) as { id: string }
+
+    expect(result.id).toEqual(expect.any(String))
+    expect(result.id.length).toBeGreaterThan(0)
+  })
+
+  it('should throw a descriptive APIError for an invalid API key', async () => {
+    // Exercises the real Resend error path end-to-end (JSON 401/403 body),
+    // proving the adapter surfaces the reason instead of a JSON parse error.
+    await expect(() =>
+      adapter('re_invalid_key_for_testing').sendEmail({
+        from: 'Payload <onboarding@resend.dev>',
+        subject: 'Should fail',
+        text: 'Should fail',
+        to: 'delivered@resend.dev',
+      }),
+    ).rejects.toThrow(/Error sending email/)
+  })
+})