### Question:
ExtractedMathPDDocument implements Comparable<ExtractedMathPDDocument>, Serializable { public String getPlainText() { if ( plainText == null ){ plainText = WikiTextUtils.MATH_TAG_PATTERN.matcher(text).replaceAll(""); } return plainText; } ExtractedMathPDDocument();  ExtractedMathPDDocument(String title, String text); void setPlainText(String plainText); static String getNameFromId(String id); static String getPageFromId(String id); Map<String, Double> getHistogramBvar(); String getPlainText(); void setHistogramBvar(Map<String, Double> histogramBvar); Map<String, Double> getHistogramCn(); void setHistogramCn(Map<String, Double> histogramCn); Map<String, Double> getHistogramCsymbol(); void setHistogramCsymbol(Map<String, Double> histogramCsymbol); Map<String, Double> getHistogramCi(); void setHistogramCi(Map<String, Double> histogramCi); String getTitle(); void setTitle(String title); String getText(); void setText(String text); String getId(); @Override String toString(); @Override int compareTo(ExtractedMathPDDocument o); @Override int hashCode(); String getName(); void setName(String name); String getPage(); void setPage(String page); void mergeOtherIntoThis(ExtractedMathPDDocument other); public String title; public String text; public String name; }### Answer:
@Test public void getPlainText() throws Exception { String input = "For a constant potential, <math>V</math> , the solution is oscillatory for <math>E > V_{0}</math> " + "and exponential for <math>E < V_{0}\n</math> , corresponding to energies that are allowed or disallowed " + "in classical mechanics. "; String expected = "For a constant potential, , the solution is oscillatory for and exponential for , corresponding to energies that are allowed or disallowed in classical mechanics. "; final ExtractedMathPDDocument document = new ExtractedMathPDDocument("test", input); CharSequence actual = document.getPlainText(); assertEquals(expected, actual); }