Add unit tests for DateHistogramAggregator (#22714)

Adds unit tests for the date histogram aggregator. Relates #22278
elastic · Jan 20, 2017 · f7dc7e2 · f7dc7e2
1 parent 12d7ec2
commit f7dc7e2
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Showing 2 changed files with 411 additions and 4 deletions.
diff --git a/core/src/test/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java b/core/src/test/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java
@@ -172,10 +172,13 @@ protected <A extends InternalAggregation, C extends Aggregator> A searchAndReduc
                     aggs.add(a.buildAggregation(0L));
                 }
             }
-            @SuppressWarnings("unchecked")
-            A internalAgg = (A) aggs.get(0).doReduce(aggs,
-                new InternalAggregation.ReduceContext(root.context().bigArrays(), null));
-            return internalAgg;
+            if (aggs.isEmpty()) {
+                return null;
+            } else {
+                @SuppressWarnings("unchecked")
+                A internalAgg = (A) aggs.get(0).doReduce(aggs, new InternalAggregation.ReduceContext(root.context().bigArrays(), null));
+                return internalAgg;
+            }
         }
     }