Add unit test for NoOpResult

Relates #66269

server/src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java

@@ -4119,9 +4119,13 @@ public class InternalEngineTests extends EngineTestCase {
      * Verifies that a segment containing only no-ops can be used to look up _version and _seqno.
      */
     public void testSegmentContainsOnlyNoOps() throws Exception {
-        Engine.NoOpResult noOpResult = engine.noOp(new Engine.NoOp(1, primaryTerm.get(),
+        final long seqNo = randomLongBetween(0, 1000);
+        final long term = this.primaryTerm.get();
+        Engine.NoOpResult noOpResult = engine.noOp(new Engine.NoOp(seqNo, term,
             randomFrom(Engine.Operation.Origin.values()), randomNonNegativeLong(), "test"));
         assertThat(noOpResult.getFailure(), nullValue());
+        assertThat(noOpResult.getSeqNo(), equalTo(seqNo));
+        assertThat(noOpResult.getTerm(), equalTo(term));
         engine.refresh("test");
         Engine.DeleteResult deleteResult = engine.delete(replicaDeleteForDoc("id", 1, 2, randomNonNegativeLong()));
         assertThat(deleteResult.getFailure(), nullValue());
@@ -4151,6 +4155,8 @@ public class InternalEngineTests extends EngineTestCase {
                 case NO_OP:
                     Engine.NoOpResult noOp = engine.noOp(new Engine.NoOp(i, primaryTerm.get(),
                         randomFrom(Engine.Operation.Origin.values()), randomNonNegativeLong(), ""));
+                    assertThat(noOp.getTerm(), equalTo(primaryTerm.get()));
+                    assertThat(noOp.getSeqNo(), equalTo((long) i));
                     assertThat(noOp.getFailure(), nullValue());
                     break;
                 default: