Fix TranslogTests#testStats (#55085)

This test failed because it was executed too fast :D. If creating the 
first translog generation and checking the translog stats happen within
the same second, then the earliestLastModifiedAge will be zero.

Closes #55064

server/src/test/java/org/elasticsearch/index/translog/TranslogTests.java

@@ -419,6 +419,8 @@ public void testFindEarliestLastModifiedAge() throws IOException {
     }
 
     public void testStats() throws IOException {
+        assertThat(translog.getCurrent().getLastModifiedTime(), lessThanOrEqualTo(System.currentTimeMillis()));
+        long lastModifiedAge = System.currentTimeMillis() - translog.getCurrent().getLastModifiedTime();
         // self control cleaning for test
         translog.getDeletionPolicy().setRetentionSizeInBytes(1024 * 1024);
         translog.getDeletionPolicy().setRetentionAgeInMillis(3600 * 1000);
@@ -436,7 +438,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(164L));
             assertThat(stats.getUncommittedOperations(), equalTo(1));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(164L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
 
         translog.add(new Translog.Delete("test", "2", 1, primaryTerm.get(), newUid("2")));
@@ -446,7 +448,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(213L));
             assertThat(stats.getUncommittedOperations(), equalTo(2));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(213L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
 
         translog.add(new Translog.Delete("test", "3", 2, primaryTerm.get(), newUid("3")));
@@ -456,7 +458,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(262L));
             assertThat(stats.getUncommittedOperations(), equalTo(3));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(262L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
 
         translog.add(new Translog.NoOp(3, 1, randomAlphaOfLength(16)));
@@ -466,7 +468,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(304L));
             assertThat(stats.getUncommittedOperations(), equalTo(4));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(304L));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
 
         final long expectedSizeInBytes = 359L;
@@ -477,7 +479,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(expectedSizeInBytes));
             assertThat(stats.getUncommittedOperations(), equalTo(4));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(expectedSizeInBytes));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
 
         {
@@ -507,7 +509,7 @@ public void testStats() throws IOException {
             assertThat(stats.getTranslogSizeInBytes(), equalTo(expectedSizeInBytes));
             assertThat(stats.getUncommittedOperations(), equalTo(0));
             assertThat(stats.getUncommittedSizeInBytes(), equalTo(firstOperationPosition));
-            assertThat(stats.getEarliestLastModifiedAge(), greaterThan(1L));
+            assertThat(stats.getEarliestLastModifiedAge(), greaterThanOrEqualTo(lastModifiedAge));
         }
     }