TransMeta_PDI_13634_Test.java

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 * Pentaho Data Integration
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package org.pentaho.di.trans;

import org.junit.BeforeClass;
import org.junit.Test;
import org.pentaho.di.core.KettleEnvironment;
import org.pentaho.di.core.row.RowMetaInterface;
import org.pentaho.di.trans.step.StepMeta;

import static org.junit.Assert.assertEquals;

/**
 * This test was created after <a href="http://jira.pentaho.com/browse/PDI-13634">PDI-13634</a>. It verifies the process
 * of previewing field in a transformation, that contains a {@linkplain org.pentaho.di.trans.steps.mapping.Mapping
 * Mapping step}.
 * <p/>
 * The input transformation is a simplified version of the one, attached to the ticket. It has a linear structure:
 * <tt>generator -> mapper -> captor</tt>. <tt>mapper</tt> invokes the internal transformation, that has the following
 * structure: <pre>
 *   input -> dummy1 ---->
 *              |         |
 *            dummy2 -> lookup -> output
 * </pre>
 *
 * @author Andrey Khayrutdinov
 */
public class TransMeta_PDI_13634_Test {

  @BeforeClass
  public static void initKettle() throws Exception {
    KettleEnvironment.init();
  }

  @Test
  public void shouldNotShareRowMetaInterfaceAmongDifferentSteps() throws Exception {
    TransMeta transMeta = new TransMeta( "testfiles/org/pentaho/di/trans/pdi-13634.ktr" );
    StepMeta mapper = transMeta.findStep( "mapper" );
    StepMeta captor = transMeta.findStep( "captor" );

    RowMetaInterface mapperOutputPreview = transMeta.getStepFields( mapper, captor, null );
    assertPreviewRows( mapperOutputPreview );

    RowMetaInterface captorInputPreview = transMeta.getPrevStepFields( captor, null );
    assertPreviewRows( captorInputPreview );
  }

  /**
   * Checks if <tt>preview</tt> contains the proper data. For the input example, it is two String fields: <tt>value</tt>
   * and <tt>new_value</tt>.
   *
   * @param preview previewed fields
   */
  private static void assertPreviewRows( RowMetaInterface preview ) {
    assertEquals( "There should be two fields", 2, preview.size() );
    assertEquals( "The first should be 'value'", "value", preview.getValueMeta( 0 ).getName() );
    assertEquals( "The second should be 'new_value'", "new_value", preview.getValueMeta( 1 ).getName() );
  }
}