in src/lib.rs [706:719]
fn test_flexible_plaintext_addition() {
let t = 199;
let fv = crate::default_with_plaintext_mod(t);
let (pk, sk) = fv.generate_keypair();
let plain_modulus = fv.t.clone();
let v = vec![Scalar::from_u32(t-1, &plain_modulus); fv.n];
let w = vec![Scalar::from_u32(t-1, &plain_modulus); fv.n];
let v_plus_w = vec![Scalar::from_u32(t-2, &plain_modulus); fv.n];
let mut ctv = fv.encrypt(&v, &pk);
let ctw = fv.encrypt(&w, &pk);
fv.add_inplace(&mut ctv, &ctw);
let pt_actual: Vec<Scalar>= fv.decrypt(&ctv, &sk);
assert_eq!(pt_actual, v_plus_w);
}