def test_scalar_constant():
mesh = UnitCubeMesh(MPI.comm_world, 2, 2, 2)
c = Constant(mesh, 1.0)
assert c.value.shape == ()
assert c.value == 1.0
c.value += 1.0
assert c.value == 2.0
c.value = 3.0
assert c.value == 3.0
def test_wrong_dim():
mesh = UnitCubeMesh(MPI.comm_world, 2, 2, 2)
c = Constant(mesh, [1.0, 2.0])
assert c.value.shape == (2, )
with pytest.raises(ValueError):
c.value = [1.0, 2.0, 3.0]
