Program: 11586
Project: 11586
Buggy source:
protected final void testReadGood(final String sBaseDir){
  final File aBaseDir=new File(sBaseDir);
  if (!aBaseDir.exists())   throw new IllegalArgumentException("String_Node_Str" + sBaseDir + "String_Node_Str");
  for (  final File aFile : new FileSystemRecursiveIterator(aBaseDir).withFilter(IFileFilter.filenameEndsWith("String_Node_Str"))) {
    final String sKey=aFile.getAbsolutePath();
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sKey);
    final CollectingCSSParseErrorHandler aErrorHdl=new CollectingCSSParseErrorHandler(new LoggingCSSParseErrorHandler());
    m_aReaderSettings.setCustomErrorHandler(aErrorHdl);
    final CascadingStyleSheet aCSS=CSSReader.readFromFile(aFile,m_aReaderSettings);
    assertNotNull(sKey,aCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + aErrorHdl.getAllParseErrors().toString());
    CommonsTestHelper.testDefaultSerialization(aCSS);
    String sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(true)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sCSS);
    final CascadingStyleSheet aCSSReRead=CSSReader.readFromStringReader(sCSS,m_aReaderSettings);
    assertNotNull("String_Node_Str" + sKey + "String_Node_Str"+ sCSS,aCSSReRead);
    assertEquals(sKey,aCSS,aCSSReRead);
    sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(false)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sCSS);
    assertEquals(sKey,aCSS,CSSReader.readFromStringReader(sCSS,m_aReaderSettings));
    sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(false).setRemoveUnnecessaryCode(true)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    assertNotNull(sKey,CSSReader.readFromStringReader(sCSS,m_aReaderSettings));
    m_aWriterSettings.setRemoveUnnecessaryCode(false);
  }
}

Fixed version (ground truth):
protected final void testReadGood(final String sBaseDir){
  final File aBaseDir=new File(sBaseDir);
  if (!aBaseDir.exists())   throw new IllegalArgumentException("String_Node_Str" + sBaseDir + "String_Node_Str");
  for (  final File aFile : new FileSystemRecursiveIterator(aBaseDir).withFilter(IFileFilter.filenameEndsWith("String_Node_Str"))) {
    final String sKey=aFile.getAbsolutePath();
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sKey);
    final CollectingCSSParseErrorHandler aErrorHdl=new CollectingCSSParseErrorHandler(new LoggingCSSParseErrorHandler());
    m_aReaderSettings.setCustomErrorHandler(aErrorHdl);
    final CascadingStyleSheet aCSS=CSSReader.readFromFile(aFile,m_aReaderSettings);
    assertNotNull(sKey,aCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + aErrorHdl.getAllParseErrors().toString());
    CommonsTestHelper.testDefaultSerialization(aCSS);
    String sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(true)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sCSS);
    final CascadingStyleSheet aCSSReRead=CSSReader.readFromStringReader(sCSS,m_aReaderSettings);
    assertNotNull("String_Node_Str" + sKey + "String_Node_Str"+ sCSS,aCSSReRead);
    assertEquals(sKey + "String_Node_Str" + sCSS,aCSS,aCSSReRead);
    sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(false)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    if (m_bDebug)     m_aLogger.info("String_Node_Str" + sCSS);
    assertEquals(sKey,aCSS,CSSReader.readFromStringReader(sCSS,m_aReaderSettings));
    sCSS=new CSSWriter(m_aWriterSettings.setOptimizedOutput(false).setRemoveUnnecessaryCode(true)).getCSSAsString(aCSS);
    assertNotNull(sKey,sCSS);
    assertNotNull(sKey,CSSReader.readFromStringReader(sCSS,m_aReaderSettings));
    m_aWriterSettings.setRemoveUnnecessaryCode(false);
  }
}