diff --git a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/RollupResponseTranslationTests.java b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/RollupResponseTranslationTests.java
index 98e3ad8197a51..35d9f0d133a3d 100644
--- a/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/RollupResponseTranslationTests.java
+++ b/x-pack/plugin/rollup/src/test/java/org/elasticsearch/xpack/rollup/RollupResponseTranslationTests.java
@@ -508,10 +508,12 @@ public void testMismatch() throws IOException {
         BigArrays bigArrays = new MockBigArrays(new MockPageCacheRecycler(Settings.EMPTY), new NoneCircuitBreakerService());
         ScriptService scriptService = mock(ScriptService.class);
         InternalAggregation.ReduceContext reduceContext = new InternalAggregation.ReduceContext(bigArrays, scriptService, true);
-        Exception e = expectThrows(RuntimeException.class,
+        ClassCastException e = expectThrows(ClassCastException.class,
                 () -> RollupResponseTranslator.combineResponses(msearch, reduceContext));
-        assertThat(e.getMessage(), equalTo("org.elasticsearch.search.aggregations.metrics.geobounds.InternalGeoBounds " +
-                "cannot be cast to org.elasticsearch.search.aggregations.InternalMultiBucketAggregation"));
+        assertThat(e.getMessage(),
+            containsString("org.elasticsearch.search.aggregations.metrics.geobounds.InternalGeoBounds"));
+        assertThat(e.getMessage(),
+            containsString("org.elasticsearch.search.aggregations.InternalMultiBucketAggregation"));
     }
 
     public void testDateHisto() throws IOException {