question: public void testNullStoredField ( ) throws Exception { Directory dir = newDirectory ( ) ; Analyzer analyzer = new MockAnalyzer ( random ( ) ) ; IndexWriter iw = new IndexWriter ( dir , new IndexWriterConfig ( analyzer ) ) ; Document doc = new Document ( ) ; iw . addDocument ( doc ) ; expectThrows ( IllegalArgumentException . class , null ) ; assertNull ( iw . getTragicException ( ) ) ; iw . close ( ) ; DirectoryReader r = DirectoryReader . open ( dir ) ; assertEquals ( 1 , r . numDocs ( ) ) ; r . close ( ) ; dir . close ( ) ; }
target:  test a null string value doesn't abort the entire segment 