fixed failing test.

Author: AlexSilaghiWBT

src/test/java/edu/stanford/protege/gateway/validators/ValidatorServiceTest.java

@@ -3,6 +3,7 @@
 import edu.stanford.protege.gateway.EntityIsMissingException;
 import edu.stanford.protege.gateway.dto.CreateEntityDto;
 import edu.stanford.protege.gateway.ontology.commands.*;
+import edu.stanford.protege.webprotege.common.Page;
 import edu.stanford.protege.webprotege.ipc.CommandExecutor;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -34,6 +35,7 @@ class ValidatorServiceTest {
     void setUp() {
         MockitoAnnotations.openMocks(this);
         validatorService = new ValidatorService(isExistingProjectExecutor, filterExistingEntitiesExecutor, getEntitySearchExecutor);
+        when(getEntitySearchExecutor.execute(any(),any())).thenReturn(CompletableFuture.supplyAsync(() -> new GetExistingClassesForApiResponse(Page.emptyPage())));
     }
 
     @Test