### Question:
FilePerIndexDirectory extends ColumnIndexDirectory { @Override public PinotDataBuffer getBuffer(String column, ColumnIndexType type) throws IOException { IndexKey key = new IndexKey(column, type); return getReadBufferFor(key); } protected  FilePerIndexDirectory(File segmentDirectory, SegmentMetadataImpl metadata, ReadMode readMode); @Override PinotDataBuffer getBuffer(String column, ColumnIndexType type); @Override PinotDataBuffer newBuffer(String column, ColumnIndexType type, long sizeBytes); @Override boolean hasIndexFor(String column, ColumnIndexType type); @Override void close(); @Override void removeIndex(String columnName, ColumnIndexType indexType); @Override boolean isIndexRemovalSupported();  }### Answer:
@Test(expectedExceptions = RuntimeException.class) public void testMissingIndex() throws IOException { try (FilePerIndexDirectory fpiDirectory = new FilePerIndexDirectory(TEMP_DIR, segmentMetadata, ReadMode.mmap)) { fpiDirectory.getBuffer("noSuchColumn", ColumnIndexType.DICTIONARY); } }