### Question:
TransChangedExtensionPoint implements ExtensionPointInterface, ContentChangedListener { @Override public void callExtensionPoint( final LogChannelInterface log, Object object ) throws KettleException { if ( object != null && object instanceof TransMeta ) { TransMeta transMeta = (TransMeta) object; if ( !transMeta.getContentChangedListeners().contains( this ) ) { transMeta.addContentChangedListener( this ); } } }  @Override void callExtensionPoint( final LogChannelInterface log, Object object ); @Override void contentChanged( Object object ); @Override void contentSafe( Object object );  }### Answer:
@Test public void testCallExtensionPoint() throws Exception { TransChangedExtensionPoint extensionPoint = new TransChangedExtensionPoint(); extensionPoint.callExtensionPoint( null, null ); extensionPoint.callExtensionPoint( null, transMeta ); }