CIRC-2117 Return empty result when search doesn't find anything (#1485)

* CIRC-2117: return empty if no instance found

src/main/java/org/folio/circulation/infrastructure/storage/SearchRepository.java

@@ -1,6 +1,7 @@
 package org.folio.circulation.infrastructure.storage;
 
 import static org.folio.circulation.support.StringUtil.urlEncode;
+import static org.folio.circulation.support.results.Result.emptyAsync;
 import static org.folio.circulation.support.results.Result.failed;
 import static org.folio.circulation.support.results.ResultBinding.flatMapResult;
 import static org.folio.circulation.support.results.ResultBinding.mapResult;
@@ -62,9 +63,9 @@ private Result<MultipleRecords<SearchInstance>> mapResponseToInstances(Response
 
   private CompletableFuture<Result<SearchInstance>> updateItemDetails(SearchInstance searchInstance) {
     log.debug("updateItemDetails:: searchInstance {}", () -> searchInstance);
-    if (searchInstance == null) {
-      return CompletableFuture.completedFuture(failed(new BadRequestFailure(
-        "Search result is empty")));
+    if (searchInstance == null || searchInstance.getId() == null) {
+      log.info("updateItemDetails:: searchInstance is empty");
+      return emptyAsync();
     }
 
     Map<String, List<Item>> itemsByTenant = searchInstance.getItems()

src/test/java/api/ItemsByInstanceResourceTest.java

@@ -4,6 +4,7 @@
 import static api.support.APITestContext.setTempTenantId;
 import static api.support.http.InterfaceUrls.itemsByInstanceUrl;
 import static api.support.matchers.JsonObjectMatcher.hasJsonPath;
+import static org.folio.HttpStatus.HTTP_OK;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.allOf;
 import static org.hamcrest.Matchers.hasItem;
@@ -77,6 +78,17 @@ void canGetInstanceById() {
       hasJsonPath("tenantId", is(TENANT_ID_UNIVERSITY)))));
   }
 
+  @Test
+  void canGetEmptyResult() {
+    UUID instanceId = UUID.randomUUID();
+
+    ResourceClient.forSearchClient().replace(instanceId, new JsonObject());
+    Response response = get(String.format("query=(id==%s)", instanceId), HTTP_OK.toInt());
+    JsonObject responseJson = response.getJson();
+
+    assertThat(responseJson.isEmpty(), is(true));
+  }
+
   private Response get(String query, int expectedStatusCode) {
     return restAssuredClient.get(itemsByInstanceUrl(query), expectedStatusCode,
       "items-by-instance-request");