fix: distinguish email service errors and validate send receipts

tests/email-notifications.test.mjs

@@ -0,0 +1,19 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {emailConfiguration,sendEmailTest} from '../src/services/emailNotifications.js';
+test('email configuration errors differ from an explicitly unconfigured service',async()=>{
+ const fetch=globalThis.fetch;
+ try{
+  globalThis.fetch=async()=>Response.json({success:false,error:'Unavailable'},{status:503});await assert.rejects(emailConfiguration(),/Unavailable/);
+  globalThis.fetch=async()=>Response.json({success:true,configured:false});assert.equal((await emailConfiguration()).configured,false);
+  globalThis.fetch=async()=>Response.json({success:true});await assert.rejects(emailConfiguration(),/doğrulanamadı/);
+ }finally{globalThis.fetch=fetch;}
+});
+test('email test requires HTTP success and a provider receipt, without retrying',async()=>{
+ const fetch=globalThis.fetch;let calls=0;
+ try{
+  globalThis.fetch=async()=>{calls++;return Response.json({success:true,to:'qa@example.test'});};await assert.rejects(sendEmailTest([]),/posta kutunuzu/);assert.equal(calls,1);
+  globalThis.fetch=async()=>Response.json({success:true,id:'qa-id',to:'qa@example.test'},{status:502});await assert.rejects(sendEmailTest([]));
+  globalThis.fetch=async()=>Response.json({success:true,id:'qa-id',to:'qa@example.test'});assert.equal((await sendEmailTest([])).id,'qa-id');
+ }finally{globalThis.fetch=fetch;}
+});