add test

processing/src/main/java/io/druid/query/topn/TopNQueryQueryToolChest.java

@@ -532,7 +532,7 @@ public class TopNQueryQueryToolChest extends QueryToolChest<Result<TopNResultVal
     return Ordering.natural();
   }
 
-  private static class ThresholdAdjustingQueryRunner implements QueryRunner<Result<TopNResultValue>>
+  static class ThresholdAdjustingQueryRunner implements QueryRunner<Result<TopNResultValue>>
   {
     private final QueryRunner<Result<TopNResultValue>> runner;
     private final TopNQueryConfig config;

processing/src/test/java/io/druid/query/topn/TopNQueryQueryToolChestTest.java

@@ -22,25 +22,37 @@ package io.druid.query.topn;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Maps;
+import com.metamx.common.guava.Sequence;
 import io.druid.granularity.QueryGranularity;
 import io.druid.jackson.DefaultObjectMapper;
 import io.druid.query.CacheStrategy;
+import io.druid.query.Query;
+import io.druid.query.QueryRunner;
+import io.druid.query.QueryRunnerFactory;
+import io.druid.query.QueryRunnerTestHelper;
 import io.druid.query.Result;
 import io.druid.query.TableDataSource;
+import io.druid.query.TestQueryRunners;
 import io.druid.query.aggregation.AggregatorFactory;
 import io.druid.query.aggregation.CountAggregatorFactory;
 import io.druid.query.dimension.DefaultDimensionSpec;
 import io.druid.query.spec.MultipleIntervalSegmentSpec;
+import io.druid.segment.IncrementalIndexSegment;
+import io.druid.segment.TestIndex;
 import org.joda.time.DateTime;
 import org.joda.time.Interval;
 import org.junit.Assert;
 import org.junit.Test;
 
 import java.util.Arrays;
+import java.util.Map;
 
 public class TopNQueryQueryToolChestTest
 {
 
+  private static final String segmentId = "testSegment";
+
   @Test
   public void testCacheStrategy() throws Exception
   {
@@ -93,4 +105,72 @@ public class TopNQueryQueryToolChestTest
 
     Assert.assertEquals(result, fromCacheResult);
   }
+
+  @Test
+  public void testMinTopNThreshold() throws Exception
+  {
+    TopNQueryConfig config = new TopNQueryConfig();
+    final TopNQueryQueryToolChest chest = new TopNQueryQueryToolChest(
+        config,
+        QueryRunnerTestHelper.NoopIntervalChunkingQueryRunnerDecorator()
+    );
+    QueryRunnerFactory factory = new TopNQueryRunnerFactory(
+        TestQueryRunners.getPool(),
+        chest,
+        QueryRunnerTestHelper.NOOP_QUERYWATCHER
+    );
+    QueryRunner<Result<TopNResultValue>> runner = QueryRunnerTestHelper.makeQueryRunner(
+        factory,
+        new IncrementalIndexSegment(TestIndex.getIncrementalTestIndex(false), segmentId)
+    );
+
+    Map<String, Object> context = Maps.newHashMap();
+    context.put("minTopNThreshold", 500);
+
+    TopNQueryBuilder builder = new TopNQueryBuilder()
+        .dataSource(QueryRunnerTestHelper.dataSource)
+        .granularity(QueryRunnerTestHelper.allGran)
+        .dimension(QueryRunnerTestHelper.placementishDimension)
+        .metric(QueryRunnerTestHelper.indexMetric)
+        .intervals(QueryRunnerTestHelper.fullOnInterval)
+        .aggregators(QueryRunnerTestHelper.commonAggregators);
+
+    TopNQuery query1 = builder.threshold(10).context(null).build();
+    MockQueryRunner mockRunner = new MockQueryRunner(runner);
+    new TopNQueryQueryToolChest.ThresholdAdjustingQueryRunner(mockRunner, config)
+        .run(query1, ImmutableMap.<String, Object>of());
+    Assert.assertEquals(1000, mockRunner.query.getThreshold());
+
+    TopNQuery query2 = builder.threshold(10).context(context).build();
+
+    new TopNQueryQueryToolChest.ThresholdAdjustingQueryRunner(mockRunner, config)
+        .run(query2, ImmutableMap.<String, Object>of());
+    Assert.assertEquals(500, mockRunner.query.getThreshold());
+
+    TopNQuery query3 = builder.threshold(2000).context(context).build();
+    new TopNQueryQueryToolChest.ThresholdAdjustingQueryRunner(mockRunner, config)
+        .run(query3, ImmutableMap.<String, Object>of());
+    Assert.assertEquals(2000, mockRunner.query.getThreshold());
+  }
+
+  static class MockQueryRunner implements QueryRunner<Result<TopNResultValue>>
+  {
+    private final QueryRunner<Result<TopNResultValue>> runner;
+    TopNQuery query = null;
+
+    MockQueryRunner(QueryRunner<Result<TopNResultValue>> runner)
+    {
+      this.runner = runner;
+    }
+
+    @Override
+    public Sequence<Result<TopNResultValue>> run(
+        Query<Result<TopNResultValue>> query,
+        Map<String, Object> responseContext
+    )
+    {
+      this.query = (TopNQuery) query;
+      return query.run(runner, responseContext);
+    }
+  }
 }