'block_diag with one matrix'

def test_block_diag_1(self):

    assert_equal(construct.block_diag([[1, 0]]).todense(), matrix([[1, 0]]))
    assert_equal(construct.block_diag([[[1, 0]]]).todense(), matrix([[1, 0]]))
    assert_equal(construct.block_diag([[[1], [0]]]).todense(), matrix([[1], [0]]))
    assert_equal(construct.block_diag([1]).todense(), matrix([[1]]))
