code: def test_table_columnar(self):
      data = {"a": [1, 2, 3], "b": [4, 5, 6]}
      tbl = Table(data)
      assert tbl.columns() == ["a", "b"]
      assert tbl.size() == 3
      assert tbl.schema() == {"a": int, "b": int}
  
imports: import sys
  from datetime import date, datetime
  from perspective.core.exception import PerspectiveError
  from perspective.table import Table
  from perspective.table._state import _PerspectiveStateManager
  from perspective.table.libpsppy import PerspectiveCppError, t_filter_op
  from pytest import raises
label_desc: Use image node_id 21 for calling the TestTable obj's underlying member method code with example usage: obj.test_table_columnar() without return types