Cassandra-Unit is a Java Utility test tool that helps us write isolated Junit Tests without having to mock or connecting to real cassandra. There are several ways to use the Cassandra-Unit in a Java project. Before to start the entire project is available at my Git Hub account: Cassandra-Unit Git Hub

This blog will describe how using Junit4 rule annotation (@Rule) cassandra-unit can be used.

  1. Create a CQL file describing the table that needs to be created and the data that needs to be inserted.
 id int,
 name text,


INSERT INTO employee (id, name) VALUES(1, 'Lakshay');
INSERT INTO employee (id, name) VALUES(2, 'George');
INSERT INTO employee (id, name) VALUES(3, 'Andy');
INSERT INTO employee (id, name) VALUES(4, 'Nicole');

   2. Create Junit Test class using CassandraCQLUnit Rule annotation by mentioning the name of the CQL file created in Step 1 and the Cassandra Keyspace name that you prefer. This in itself sets up and starts an embedded Cassandra. This Cassandra unit active instance should be passed to the DAO/Repository class so that the cassandra session can be used to query the started database.

public CassandraCQLUnit cassandraCQLUnit = new CassandraCQLUnit(new ClassPathCQLDataSet("cql/employee.cql", "emp_keyspace"));

private EmpRepository empRepository;

 public void setUp() throws Exception {
     // pass the cassandra session to the class.
     empRepository = new EmpRepository(cassandraCQLUnit.session);

 public void testFindEmployeeById() throws Exception {
     EmpDetails empExpected = new EmpDetails(1, "Lakshay");
     EmpDetails empGenerated = empRepository.findEmployeeById(1);
     assertEquals(empExpected, empGenerated);

3. The Java class that need to be tested is the following:

public class EmpRepository {

   private Session session;

   public EmpRepository(Session session) {
      this.session = session;

   public EmpDetails findEmployeeById(int id) {
     EmpDetails empDetails = null;
     ResultSet resultSet = session.execute("select * from employee where id="+ id);
     for (Row row: resultSet) {
      empDetails = new EmpDetails(row.getInt("id"), row.getString("name"));
    return empDetails;




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