Added : prefer header test

Pagination.http

@@ -16,4 +16,16 @@ GET {{baseUrl}}/products?limit=40&offset=7
     test('OK content-range', () => {
     equal(response.headers['content-range'], '7-46/*');
     });
-}}
+}}
+
+GET {{baseUrl}}/products?limit=20&offset=40
+Prefer: count=exact
+?? status == 206 
+{{
+    const { equal } = require('assert');
+    let responseItems = JSON. parse(response.body);
+    let itemsCount = responseItems.length;
+    test('OK content-range', () => {
+    equal(response.headers['content-range'], '40-59/77');
+    });
+}}