NullPointerException thrown from ESIntegTestCase - elasticsearch

Question

I am using Elasticsearch version 2.4.4.
Then I had created test case derived from ESIntegTestCase, something like:
public class ELSTest extends ESIntegTestCase {
#Override
protected Settings nodeSettings ( int nodeOrdinal ) {
return Settings.builder().put( super.nodeSettings( nodeOrdinal ) )
.put( super.nodeSettings( nodeOrdinal ) )
.put( IndexMetaData.SETTING_NUMBER_OF_SHARDS, 1 )
.put( IndexMetaData.SETTING_NUMBER_OF_REPLICAS, 1 )
.put( Node.HTTP_ENABLED, true )
.build();
}
#BeforeClass
public void setup () throws Exception {
createIndex( "idx" ); // line 57
ensureGreen( "idx" );
}
}
After resolving "jar hell" problem and reading bunch of pages about ESIntegTestCase I got new one.
java.lang.NullPointerException
at org.elasticsearch.test.ESIntegTestCase.client(ESIntegTestCase.java:657)
at org.elasticsearch.test.ESIntegTestCase.client(ESIntegTestCase.java:650)
at org.elasticsearch.test.ESIntegTestCase.prepareCreate(ESIntegTestCase.java:763)
at com.company.ELSTest.setup(ELSTest.java:57)
What can be the reason for it? I mean the one where ESIntegTestCase class throws NPE in the line:
Client client = cluster().client();
It seems like cluster is not initialized. What is the proper very basic class setup, to start elasticsearch in tests?

Answer 1

Answering myself :-)
The documentation is located at: integration tests
There are the following extentions needed:
Important limitation is that ESIntegTestCase class will work only with JUnit. There is no easy way to get it working with e.g. TestNG - explanation follows.
Start JUnit with additional parameters:
-Dtests.jarhell.check=false
to avoid jar hell
-Dtests.security.manager=false
to avoid java.security.AccessControlException: access denied
Class is declared as following:
#RunWith( com.carrotsearch.randomizedtesting.RandomizedRunner.class )
public class ELSTest extends ESIntegTestCase {
#Before
public void setup () throws Exception {
beforeClass(); // against NullPointerException in ESIntegTestCase
createIndex( "idx" );
ensureGreen( "idx" );
// ...
}
}
Remarks:
#RunWith is needed to avoid java.lang.IllegalStateException: No context information for thread:
and this is a reason why e.g. TestNG cannot be used - TestNG has no RunWith annotation.
#Before cannot be changed to #BeforeClass as beforeClass() method cannot be called from static context.
The method nodeSettings ( int nodeOrdinal ) is not mandatory.