### Question:
RapidEyeMetadata extends XmlMetadata { public RationalCoefficients getRationalPolinomialCoefficients() { RationalCoefficients coefficients = null; MetadataElement currentElement; if ((currentElement = rootElement.getElement(RapidEyeConstants.TAG_RPC)) != null) { coefficients = new RationalCoefficients(); String data, attrName; for (MetadataAttribute attribute : currentElement.getAttributes()) { attrName = attribute.getName(); data = currentElement.getAttributeString(attrName, ""); if (RapidEyeConstants.TAG_LINEOFF.equals(attrName)) { coefficients.lineOffset = asInt(data); } else if (RapidEyeConstants.TAG_SAMPLEOFF.equals(attrName)) { coefficients.sampleOffset = asInt(data); } else if (RapidEyeConstants.TAG_LATOFF.equals(attrName)) { coefficients.latOffset = asFloat(data); } else if (RapidEyeConstants.TAG_LONGOFF.equals(attrName)) { coefficients.lonOffset = asFloat(data); } else if (RapidEyeConstants.TAG_HEIGHTOFF.equals(attrName)) { coefficients.heightOffset = asInt(data); } else if (RapidEyeConstants.TAG_LINESCALE.equals(attrName)) { coefficients.lineScale = asInt(data); } else if (RapidEyeConstants.TAG_SAMPLESCALE.equals(attrName)) { coefficients.sampleScale = asInt(data); } else if (RapidEyeConstants.TAG_LATSCALE.equals(attrName)) { coefficients.latScale = asInt(data); } else if (RapidEyeConstants.TAG_LONGSCALE.equals(attrName)) { coefficients.lonScale = asFloat(data); } else if (RapidEyeConstants.TAG_HEIGHTSCALE.equals(attrName)) { coefficients.heightScale = asInt(data); } else if (RapidEyeConstants.TAG_LINENUMCOEFF.equals(attrName)) { coefficients.lineNumCoefficients = asFloatArray(data, " "); } else if (RapidEyeConstants.TAG_LINEDENCOEFF.equals(attrName)) { coefficients.lineDenomCoefficients = asFloatArray(data, " "); } else if (RapidEyeConstants.TAG_SAMPLENUMCOEFF.equals(attrName)) { coefficients.sampleNumCoefficients = asFloatArray(data, " "); } else if (RapidEyeConstants.TAG_SAMPLEDENCOEFF.equals(attrName)) { coefficients.sampleDenomCoefficients = asFloatArray(data, " "); } } } return coefficients; } RapidEyeMetadata(String name); @Override String getFileName(); @Override int getNumBands(); @Override String getProductName(); @Override String getFormatName(); @Override String getMetadataProfile(); @Override String getProductDescription(); @Override int getRasterWidth(); @Override int getRasterHeight(); String getBrowseFileName(); String getMaskFileName(); @Override String[] getRasterFileNames(); SpatialReferenceSystem getReferenceSystem(); ProductData.UTC getProductStartTime(); ProductData.UTC getProductEndTime(); ProductData.UTC getCenterTime(); float getScaleFactor(int bandIndex); int getPixelFormat(); float[] getCornersLatitudes(); float[] getCornersLongitudes(); RationalCoefficients getRationalPolinomialCoefficients();  }### Answer:
@Test public void testGetRationalPolinomialCoefficients() throws Exception { assertNull(metadata.getRationalPolinomialCoefficients()); }