private void deleteStoreDirectories() {
    Preconditions.checkNotNull(configs.get(JobConfig.JOB_LOGGED_STORE_BASE_DIR));
    Preconditions.checkNotNull(configs.get(JobConfig.JOB_NON_LOGGED_STORE_BASE_DIR));
    deleteDirectory(configs.get(JobConfig.JOB_NON_LOGGED_STORE_BASE_DIR));
    deleteDirectory(configs.get(JobConfig.JOB_LOGGED_STORE_BASE_DIR));
  }
Creates an in memory stream with {@link InMemorySystemFactory} and feeds its partition with stream of messages
@param partitionData key of the map represents partitionId and value represents messages in the partition
@param descriptor describes a stream to initialize with the in memory system
samza-test/src/main/java/org/apache/samza/test/framework/TestRunner.java