public void setSQLServerInstance( String instanceName ) {
    // This is also covered/persisted by JDBC option MS SQL Server / instancename / <somevalue>
    // We want to return set <somevalue>
    // --> MSSQL.instancename
    if ( ( instanceName != null ) && ( instanceName.length() > 0 ) ) {
      addExtraOption( getPluginId(), "instance", instanceName );
    }
  }
@Test
  public void setSQLServerInstanceTest() {
    DatabaseMeta dbmeta = new DatabaseMeta();
    DatabaseInterface mssqlServerDatabaseMeta = new MSSQLServerDatabaseMeta();
    mssqlServerDatabaseMeta.setPluginId( "MSSQL" );
    DatabaseInterface mssqlServerNativeDatabaseMeta = new MSSQLServerNativeDatabaseMeta();
    mssqlServerNativeDatabaseMeta.setPluginId( "MSSQLNATIVE" );
    dbmeta.setDatabaseInterface( mssqlServerDatabaseMeta );
    dbmeta.setSQLServerInstance( "" );
    assertEquals( dbmeta.getSQLServerInstance(), null );
    dbmeta.setSQLServerInstance( "instance1" );
    assertEquals( dbmeta.getSQLServerInstance(), "instance1" );
    dbmeta.setDatabaseInterface( mssqlServerNativeDatabaseMeta );
    dbmeta.setSQLServerInstance( "" );
    assertEquals( dbmeta.getSQLServerInstance(), null );
    dbmeta.setSQLServerInstance( "instance1" );
    assertEquals( dbmeta.getSQLServerInstance(), "instance1" );
  }