diff --git a/buildSrc/src/main/groovy/org/elasticsearch/gradle/test/NodeInfo.groovy b/buildSrc/src/main/groovy/org/elasticsearch/gradle/test/NodeInfo.groovy
index 9a91c5ba138..85af2debf1b 100644
--- a/buildSrc/src/main/groovy/org/elasticsearch/gradle/test/NodeInfo.groovy
+++ b/buildSrc/src/main/groovy/org/elasticsearch/gradle/test/NodeInfo.groovy
@@ -206,6 +206,9 @@ class NodeInfo {
 
     /** Returns the data directory for this node */
     File getDataDir() {
+        if (!(dataDir instanceof File)) {
+            return new File(dataDir)
+        }
         return dataDir
     }
 
diff --git a/qa/rolling-upgrade/build.gradle b/qa/rolling-upgrade/build.gradle
index acc59bb3bed..456db46d666 100644
--- a/qa/rolling-upgrade/build.gradle
+++ b/qa/rolling-upgrade/build.gradle
@@ -39,7 +39,7 @@ task mixedClusterTest(type: RestIntegTestTask) {
     distribution = 'zip'
     clusterName = 'rolling-upgrade'
     unicastTransportUri = { seedNode, node, ant -> oldClusterTest.nodes.get(0).transportUri() }
-    dataDir = "${-> oldClusterTest.nodes[1].dataDir}"
+    dataDir = "${-> oldClusterTest.nodes[1].getDataDir()}"
   }
   systemProperty 'tests.rest.suite', 'mixed_cluster'
 
@@ -51,7 +51,7 @@ task upgradedClusterTest(type: RestIntegTestTask) {
     distribution = 'zip'
     clusterName = 'rolling-upgrade'
     unicastTransportUri = { seedNode, node, ant -> mixedClusterTest.nodes.get(0).transportUri() }
-    dataDir = "${-> oldClusterTest.nodes[0].dataDir}"
+    dataDir = "${-> oldClusterTest.nodes[0].getDataDir()}"
   }
   systemProperty 'tests.rest.suite', 'upgraded_cluster'
 }
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/10_basic.yaml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/10_basic.yaml
index a46d7aaf044..dcfa946ed64 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/10_basic.yaml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/10_basic.yaml
@@ -1,7 +1,13 @@
 ---
 "Index data and search on the mixed cluster":
-  - do:
-      bulk:
+ - do:
+     search:
+        index: test_index
+
+ - match: { hits.total: 5 } # no new indexed data, so expect the original 5 documents from the old cluster
+
+ - do:
+     bulk:
         refresh: true
         body:
           - '{"index": {"_index": "test_index", "_type": "test_type"}}'
@@ -19,4 +25,4 @@
      search:
         index: test_index
 
- - match: { hits.total: 10 }
+ - match: { hits.total: 10 } # 5 docs from old cluster, 5 docs from mixed cluster
diff --git a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yaml b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yaml
index edf9cb703d0..f6606c758a0 100644
--- a/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yaml
+++ b/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yaml
@@ -1,7 +1,13 @@
 ---
 "Index data and search on the upgraded cluster":
-  - do:
-      bulk:
+ - do:
+     search:
+       index: test_index
+
+ - match: { hits.total: 10 } # no new indexed data, so expect the original 10 documents from the old and mixed clusters
+
+ - do:
+     bulk:
         refresh: true
         body:
           - '{"index": {"_index": "test_index", "_type": "test_type"}}'
@@ -19,4 +25,4 @@
      search:
         index: test_index
 
- - match: { hits.total: 15 }
+ - match: { hits.total: 15 } # 10 docs from previous clusters plus 5 new docs