How to use it in your code

There is different possibilities to use CassandraUnit. There is two main features :

• The first is to start an embedded Cassandra Server in your JVM.
• The second is to load Data into a Cassandra Server (embedded or not).

You can use both features separately or together.

This section explains how to use API. The dataSet creation is explained in this section : How to create a DataSet?

1. Native Approach

One simple way is to use native Api :

Manage an embedded Cassandra server

• To start an embedded Cassandra Server

You just have to :

EmbeddedCassandraServerHelper.startEmbeddedCassandra();

If this method has been already called, nothing will happen, Cassandra still be started. By default, the embedded Cassandra server starts on 127.0.0.1, ports 9171 (Thrift) and 9142 (Native).

If you want to start Cassandra server on a random available port, you can use a provided alternative Cassandra yaml configuration file:

EmbeddedCassandraServerHelper.startEmbeddedCassandra(EmbeddedCassandraServerHelper.CASSANDRA_RNDPORT_YML_FILE);

It's also possible to start the embedded Cassandra server with your own Cassandra yaml configuration file (to set another port for example), you can use give your Cassandra file. This file has to be in your classpath :

EmbeddedCassandraServerHelper.startEmbeddedCassandra(String yourCassandraYamlFile);

When you start an embedded Cassandra server, it create a new empty instance.

• Clean an embedded Cassandra Server :

To clean an embedded Cassandra Server which is already started you just have to (cleaning consist in dropping all existing keyspace except "system") :

EmbeddedCassandraServerHelper.cleanEmbeddedCassandra();

At the moment there's no way to stop Cassandra. Cassandra is started in the same JVM as your tests. It will be shutdown when the JVM used by your tests is shutdown

Load data from a dataset

To load data into a started Cassandra server (embedded or not) :

DataLoader dataLoader = new DataLoader("TestCluster", "localhost:9171");
dataLoader.load(new ClassPathCQLDataSet("simpleDataSet.cql"));

2. Using AbstractCassandraUnit4TestCase

CassandraUnit provides an Abstract JUnit Test Case to extend to simplify the use of Cassandra for extends test classes.

You have to :

• create a test class AbstractCassandraUnit4TestCase
• implement method getDataSet which has to return an instance of a DataSet.

In your test case, by inheritance, you have access to getSession(). This method gives you a Datastax Cassandra java driver CqlSession You can see an example here :

package org.cassandraunit.test.cql;

import com.datastax.oss.driver.api.core.cql.ResultSet;
import org.cassandraunit.AbstractCassandraUnit4CQLTestCase;
import org.cassandraunit.dataset.CQLDataSet;
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet;
import org.junit.Test;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;

public class CQLScriptLoadWithAbstractTestCaseTest extends AbstractCassandraUnit4CQLTestCase {

    @Override
    public CQLDataSet getDataSet() {
        return new ClassPathCQLDataSet("simple.cql","keyspaceNameToCreate");
    }

    @Test
    public void should_have_started_and_execute_cql_script() throws Exception {
        ResultSet result = getSession().execute("select * from mytable WHERE id='myKey01'");
        assertThat(result.iterator().next().getString("value"), is("myValue01"));
    }
}

3. Using Junit4 @Rule

It's possible to use CassandraUnit without enforcing the use of AbstractCassandraUnit4TestCase by using @Rule You have to declare a CassandraUnit attribute in your test with the @Rule annotation

You can see an example here :

package org.cassandraunit.test.cql;

import com.datastax.oss.driver.api.core.cql.ResultSet;
import org.cassandraunit.CassandraCQLUnit;
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet;
import org.junit.Rule;
import org.junit.Test;

import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;

public class CQLScriptLoadWithJunitRuleTest {

    @Rule
    public CassandraCQLUnit cassandraCQLUnit =
            new CassandraCQLUnit(new ClassPathCQLDataSet("simple.cql","keyspaceNameToCreate"));

    @Test
    public void should_have_started_and_execute_cql_script() throws Exception {
        ResultSet result = cassandraCQLUnit.session.execute("select * from mytable WHERE id='myKey01'");
        assertThat(result.iterator().next().getString("value"), is("myValue01"));
    }
}