Add update test

x-pack/test/fleet_api_integration/apis/package_policy/update.ts

@@ -179,6 +179,36 @@ export default function (providerContext: FtrProviderContext) {
         .expect(500);
     });
 
+    it('should return a 500 if there is another package policy with the same name on a different policy', async function () {
+      const { body: agentPolicyResponse } = await supertest
+        .post(`/api/fleet/agent_policies`)
+        .set('kbn-xsrf', 'xxxx')
+        .send({
+          name: 'Test policy',
+          namespace: 'default',
+        });
+      const otherAgentPolicyId = agentPolicyResponse.item.id;
+
+      await supertest
+        .put(`/api/fleet/package_policies/${packagePolicyId2}`)
+        .set('kbn-xsrf', 'xxxx')
+        .send({
+          name: 'filetest-1',
+          description: '',
+          namespace: 'updated_namespace',
+          policy_id: otherAgentPolicyId,
+          enabled: true,
+          output_id: '',
+          inputs: [],
+          package: {
+            name: 'filetest',
+            title: 'For File Tests',
+            version: '0.1.0',
+          },
+        })
+        .expect(500);
+    });
+
     it('should work with frozen input vars', async function () {
       await supertest
         .put(`/api/fleet/package_policies/${packagePolicyId}`)