From eef10938bab9799fcafbba9c469d52e19c683fca Mon Sep 17 00:00:00 2001
From: Henning Andersen <henning.andersen@elastic.co>
Date: Tue, 27 Aug 2024 15:04:28 +0200
Subject: [PATCH] Minimal testing

---
 .../blobcache/shared/SharedBlobCacheService.java             | 5 +++++
 .../blobcache/shared/SharedBlobCacheServiceTests.java        | 1 +
 2 files changed, 6 insertions(+)

diff --git a/x-pack/plugin/blob-cache/src/main/java/org/elasticsearch/blobcache/shared/SharedBlobCacheService.java b/x-pack/plugin/blob-cache/src/main/java/org/elasticsearch/blobcache/shared/SharedBlobCacheService.java
index db5d17d20f914..b1e5bb7cec722 100644
--- a/x-pack/plugin/blob-cache/src/main/java/org/elasticsearch/blobcache/shared/SharedBlobCacheService.java
+++ b/x-pack/plugin/blob-cache/src/main/java/org/elasticsearch/blobcache/shared/SharedBlobCacheService.java
@@ -912,6 +912,11 @@ private SharedBytes.IO nonVolatileIO() {
             return io;
         }
 
+        // for use in tests *only*
+        SharedBytes.IO testOnlyNonVolatileIO() {
+            return io;
+        }
+
         /**
          * Optimistically try to read from the region
          * @return true if successful, i.e., not evicted and data available, false if evicted
diff --git a/x-pack/plugin/blob-cache/src/test/java/org/elasticsearch/blobcache/shared/SharedBlobCacheServiceTests.java b/x-pack/plugin/blob-cache/src/test/java/org/elasticsearch/blobcache/shared/SharedBlobCacheServiceTests.java
index 917b28d2ea566..8542de759c8a4 100644
--- a/x-pack/plugin/blob-cache/src/test/java/org/elasticsearch/blobcache/shared/SharedBlobCacheServiceTests.java
+++ b/x-pack/plugin/blob-cache/src/test/java/org/elasticsearch/blobcache/shared/SharedBlobCacheServiceTests.java
@@ -497,6 +497,7 @@ public void testGetMultiThreaded() throws IOException {
                                     if (yield[i] == 0) {
                                         Thread.yield();
                                     }
+                                    assertNotNull(cacheFileRegion.testOnlyNonVolatileIO());
                                     cacheFileRegion.decRef();
                                 }
                                 if (evict[i] == 0) {