### Question:
MBTileSet implements TileDataset, FileData { @Override public CoordinateReferenceSystem crs() throws IOException { return Proj.EPSG_900913; } MBTileSet(Backend backend, MBTilesOpts opts);  MBTileSet(File file); String getTileFormat(); @Override File file(); @Override Driver<?> driver(); @Override Map<Key<?>, Object> driverOptions(); @Override String name(); String title(); String description(); @Override CoordinateReferenceSystem crs(); @Override Bounds bounds(); @Override TilePyramid pyramid(); @Override Tile read(long z, long x, long y); @Override Cursor<Tile> read(long z1, long z2, long x1, long x2, long y1, long y2); @Override void close();  }### Answer:
@Test public void crs() throws IOException { assertEquals(Proj.EPSG_900913, tileset.crs()); }