[TEST] Add simple test to test RT Lucene IW settings

src/main/java/org/elasticsearch/index/engine/internal/InternalEngine.java

@@ -1281,6 +1281,11 @@ public class InternalEngine extends AbstractIndexShardComponent implements Engin
         }
     }
 
+    LiveIndexWriterConfig currentIndexWriterConfig() {
+        ensureOpen();
+        return this.indexWriter.getConfig();
+    }
+
     class FailEngineOnMergeFailure implements MergeSchedulerProvider.FailureListener {
         @Override
         public void onFailedMerge(MergePolicy.MergeException e) {

src/test/java/org/elasticsearch/index/engine/internal/InternalEngineSettingsTest.java

@@ -0,0 +1,40 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.elasticsearch.index.engine.internal;
+
+import org.elasticsearch.common.settings.ImmutableSettings;
+import org.elasticsearch.index.service.IndexService;
+import org.elasticsearch.test.ElasticsearchSingleNodeTest;
+
+import static org.hamcrest.Matchers.is;
+
+public class InternalEngineSettingsTest extends ElasticsearchSingleNodeTest {
+
+    public void testLuceneSettings() {
+        final IndexService service = createIndex("foo");
+        // INDEX_COMPOUND_ON_FLUSH
+        assertThat(engine(service).currentIndexWriterConfig().getUseCompoundFile(), is(true));
+        client().admin().indices().prepareUpdateSettings("foo").setSettings(ImmutableSettings.builder().put(InternalEngine.INDEX_COMPOUND_ON_FLUSH, false).build()).get();
+        assertThat(engine(service).currentIndexWriterConfig().getUseCompoundFile(), is(false));
+        client().admin().indices().prepareUpdateSettings("foo").setSettings(ImmutableSettings.builder().put(InternalEngine.INDEX_COMPOUND_ON_FLUSH, true).build()).get();
+        assertThat(engine(service).currentIndexWriterConfig().getUseCompoundFile(), is(true));
+    }
+
+
+}

src/test/java/org/elasticsearch/test/ElasticsearchSingleNodeTest.java

@@ -34,7 +34,9 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.BigArrays;
 import org.elasticsearch.common.util.concurrent.EsExecutors;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.index.engine.internal.InternalEngine;
 import org.elasticsearch.index.service.IndexService;
+import org.elasticsearch.index.shard.service.InternalIndexShard;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.node.Node;
 import org.elasticsearch.node.NodeBuilder;
@@ -172,6 +174,10 @@ public abstract class ElasticsearchSingleNodeTest extends ElasticsearchTestCase
         return instanceFromNode.indexServiceSafe(index);
     }
 
+    protected static InternalEngine engine(IndexService service) {
+       return ((InternalEngine)((InternalIndexShard)service.shard(0)).engine());
+    }
+
     /**
      * Create a new search context.
      */