### Question:
BitMapColumn extends BaseBitmapColumn { @Override public boolean isReadable() { initIndexReader(); boolean readable = indexReader.isReadable(); if (indexLocation.getStoreType().isPersistent()) { IoUtil.release(indexReader); } indexReader = null; return readable; } BitMapColumn(IResourceLocation parent); @Override void putBitMapIndex(int index, ImmutableBitMap bitmap); @Override void putNullIndex(ImmutableBitMap bitMap); @Override ImmutableBitMap getBitMapIndex(int index); @Override boolean isReadable(); @Override void release();  }### Answer:
@Test public void isReadable() { new BitMapColumn(new ResourceLocation("")).isReadable(); verify(bitmapReader).isReadable(); verify(bitmapReader).release(); }