message: add solver test for correct initial guess
diff: @@ -514,6 +514,14 @@ protected:
  guarded_fn(gen_in_vec<VecType>(solver, 1, 1),
  gen_out_vec<VecType>(solver, 1, 1));
  }
  + {
  + SCOPED_TRACE("Single vector with correct initial guess");
  + auto in = gen_in_vec<VecType>(solver, 1, 1);
  + auto out = gen_out_vec<VecType>(solver, 1, 1);
  + solver.ref->get_system_matrix()->apply(out.ref.get(), in.ref.get());
  + solver.dev->get_system_matrix()->apply(out.dev.get(), in.dev.get());
  + guarded_fn(std::move(in), std::move(out));
  + }
  {
  SCOPED_TRACE("Single strided vector");
  guarded_fn(gen_in_vec<VecType>(solver, 1, 2),
  