def test_refine_vertically(tmpdir):
"""Do a grid refinement vertically."""
logger.info("Read grid...")
grd = Grid(EMEGFILE)
logger.info("Read grid... done, NLAY is {}".format(grd.nlay))
logger.info("Subgrids before: %s", grd.get_subgrids())
avg_dz1 = grd.get_dz().values3d.mean()
# idea; either a scalar (all cells), or a dictionary for zone wise
grd.refine_vertically(3)
avg_dz2 = grd.get_dz().values3d.mean()
assert avg_dz1 == pytest.approx(3 * avg_dz2, abs=0.0001)
logger.info("Subgrids after: %s", grd.get_subgrids())
grd.inactivate_by_dz(0.001)
grd.to_file(join(tmpdir, "test_refined_by_3.roff"))
