diff --git a/modules/src/test/java/org/archive/modules/recrawl/ContentDigestHistoryTest.java b/modules/src/test/java/org/archive/modules/recrawl/ContentDigestHistoryTest.java
index 5b1acff1..cd007b74 100644
--- a/modules/src/test/java/org/archive/modules/recrawl/ContentDigestHistoryTest.java
+++ b/modules/src/test/java/org/archive/modules/recrawl/ContentDigestHistoryTest.java
@@ -129,6 +129,9 @@ public class ContentDigestHistoryTest extends TmpDirTestCase {
     }
 
     public void testBasics() throws InterruptedException, IOException {
+        historyStore().store.clear();
+        assertTrue(historyStore().store.isEmpty());
+
         CrawlURI curi1 = new CrawlURI(UURIFactory.getInstance("http://example.org/1"));
         // without Recorder, CrawlURI#getContentLength() returns zero, which makes
         // loader().shoudProcess() return false.
@@ -158,7 +161,8 @@ public class ContentDigestHistoryTest extends TmpDirTestCase {
         assertTrue(curi1.getContentDigestHistory().isEmpty());
 
         storer().process(curi1);
-        assertTrue(historyStore().store.isEmpty());
+        assertTrue("historyStore().store should be empty, but it is: " + historyStore().store,
+                historyStore().store.isEmpty());
         
         curi1.getContentDigestHistory().put(A_ORIGINAL_URL, "http://example.org/original");
         // curi1.getContentDigestHistory().put(A_WARC_RECORD_ID, "<urn:uuid:f00dface-d00d-d00d-d00d-0beefface0ff>");