### Question:
BlurAnalyzer extends Analyzer { public Set<String> getSubIndexNames(String indexName) { return _subIndexNameLookups.get(indexName); } BlurAnalyzer(Analyzer analyzer);  BlurAnalyzer(AnalyzerDefinition analyzerDefinition); void addSubField(String name); Set<String> getSubIndexNames(String indexName); FieldConverter getFieldConverter(String name); void putStore(String name, Store store); Store getStore(String indexName); Index getIndex(String indexName); String toJSON(); boolean isFullTextField(String fieldName); AnalyzerDefinition getAnalyzerDefinition(); void close(); int getOffsetGap(Fieldable field); int getPositionIncrementGap(String fieldName); final TokenStream reusableTokenStream(String fieldName, Reader reader); final TokenStream tokenStream(String fieldName, Reader reader); static BlurAnalyzer create(File file); static BlurAnalyzer create(InputStream inputStream); static BlurAnalyzer create(String jsonStr); static BlurAnalyzer create(Path path); static final BlurAnalyzer BLANK_ANALYZER; }### Answer:
@Test public void testGetSubFields() throws IOException { BlurAnalyzer analyzer = new BlurAnalyzer(analyzerDefinition); assertNull(analyzer.getSubIndexNames("b.d")); Set<String> subIndexNames = analyzer.getSubIndexNames("b.c"); TreeSet<String> set = new TreeSet<String>(); set.add("b.c.sub1"); set.add("b.c.sub2"); assertEquals(set, subIndexNames); }