### Question:
PopController { @GetMapping @Operation(summary = "Get Proof-of-Possession valid public keys to encrypt with") public ResponseEntity<String> pop() { KeyViewWithValidity view = rotatedKeyStore.keys().withValidity(DEFAULT_VALIDITY); return ResponseEntity.ok( new JWKSet(new ArrayList<>( exporter.export( view.encryptionKeys().stream().map(KeyAlias::getAlias).collect(Collectors.toSet()))) ).toPublicJWKSet().toJSONObject().toJSONString() ); }  @GetMapping @Operation(summary = "Get Proof-of-Possession valid keys to encrypt with") ResponseEntity<String> pop();  }### Answer:
@Test @SneakyThrows void pop() { keyStore.forRotation().rotate(); assertThat(JWKSet.parse(rest.getForObject("/pop", String.class)).getKeys()).hasSize(3); }