check the history first

Author: vladak

opengrok-web/src/test/java/org/opengrok/web/api/v1/controller/HistoryControllerTest.java

@@ -48,6 +48,7 @@
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.opengrok.web.api.v1.controller.HistoryController.getHistoryDTO;
 
 class HistoryControllerTest extends OGKJerseyTest {
@@ -130,6 +131,7 @@ void testHistoryGet() throws Exception {
                 .get();
         HistoryDTO history = response.readEntity(new GenericType<>() {
         });
+        assertNotNull(history);
         assertEquals(size, history.getEntries().size());
         assertEquals("Kryštof Tulinger <krystof.tulinger@oracle.com>", history.getEntries().get(0).getAuthor());