Fixing the reference time so that age does not change during a test (#116900)

This change makes it so that the reference time from which the "age" field of the IndexLifecycleExplainResponse
object is derived does not change for the duration of testConcurrentToXContent().

Co-authored-by: Keith Massey <[email protected]>

Author: nielsbauman

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ilm/IndexLifecycleExplainResponse.java

@@ -23,6 +23,7 @@
 
 import java.io.IOException;
 import java.util.Objects;
+import java.util.function.Supplier;
 import java.util.stream.Stream;
 
 public class IndexLifecycleExplainResponse implements ToXContentObject, Writeable {
@@ -124,6 +125,8 @@ public class IndexLifecycleExplainResponse implements ToXContentObject, Writeabl
     private final String snapshotName;
     private final String shrinkIndexName;
 
+    Supplier<Long> nowSupplier = System::currentTimeMillis; // Can be changed for testing
+
     public static IndexLifecycleExplainResponse newManagedIndexResponse(
         String index,
         String policyName,
@@ -412,11 +415,11 @@ public Integer getFailedStepRetryCount() {
         return failedStepRetryCount;
     }
 
-    public TimeValue getAge() {
+    public TimeValue getAge(Supplier<Long> now) {
         if (lifecycleDate == null) {
             return TimeValue.MINUS_ONE;
         } else {
-            return TimeValue.timeValueMillis(Math.max(0L, System.currentTimeMillis() - lifecycleDate));
+            return TimeValue.timeValueMillis(Math.max(0L, now.get() - lifecycleDate));
         }
     }
 
@@ -441,7 +444,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             builder.field(POLICY_NAME_FIELD.getPreferredName(), policyName);
             if (lifecycleDate != null) {
                 builder.timeField(LIFECYCLE_DATE_MILLIS_FIELD.getPreferredName(), LIFECYCLE_DATE_FIELD.getPreferredName(), lifecycleDate);
-                builder.field(AGE_FIELD.getPreferredName(), getAge().toHumanReadableString(2));
+                builder.field(AGE_FIELD.getPreferredName(), getAge(nowSupplier).toHumanReadableString(2));
             }
             if (phase != null) {
                 builder.field(PHASE_FIELD.getPreferredName(), phase);

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ilm/IndexLifecycleExplainResponseTests.java

@@ -34,11 +34,16 @@
 public class IndexLifecycleExplainResponseTests extends AbstractSerializingTestCase<IndexLifecycleExplainResponse> {
 
     static IndexLifecycleExplainResponse randomIndexExplainResponse() {
+        final IndexLifecycleExplainResponse indexLifecycleExplainResponse;
         if (frequently()) {
-            return randomManagedIndexExplainResponse();
+            indexLifecycleExplainResponse = randomManagedIndexExplainResponse();
         } else {
-            return randomUnmanagedIndexExplainResponse();
+            indexLifecycleExplainResponse = randomUnmanagedIndexExplainResponse();
         }
+        long now = System.currentTimeMillis();
+        // So that now is the same for the duration of the test. See #84352
+        indexLifecycleExplainResponse.nowSupplier = () -> now;
+        return indexLifecycleExplainResponse;
     }
 
     private static IndexLifecycleExplainResponse randomUnmanagedIndexExplainResponse() {
@@ -116,7 +121,7 @@ public void testNegativeAge() {
             null,
             null
         );
-        assertThat(response.getAge(), equalTo(TimeValue.ZERO));
+        assertThat(response.getAge(System::currentTimeMillis), equalTo(TimeValue.ZERO));
     }
 
     @Override