Testing Virtual Fields returning nil in Phoenix

I have a basic user schema that contains password_digest to be saved in db and virtual fields password that user will input, hashed, saved as password_digest.

The problem is when testing, I am getting password as nil the other hand I have them as non-nil. I am not sure what the best practice is when testing virtual fields.

...
Assertion with == failed
 code:  assert Accounts.get_user!(user.id()) == user
 left:  ... username: "some username", password: nil}
 right: ... username: "some username", password: "some password"}

  schema "users" do
    field :email, :string
    field :password_digest, :string
    field :username, :string

    timestamps()

    field :password, :string, virtual: true
  end

Here is the relevant codes:

def changeset(user, attrs) do
    user
    |> cast(attrs, [:username, :email, :password])
    |> hash_password
    |> validate_required([:username, :email, :password, :password_digest])
  end

  defp hash_password(changeset) do
    if password = get_change(changeset, :password) do
      changeset
      |> put_change(:password_digest, hashpwsalt(password))
    else
      changeset
    end
  end

Inside the test, I have these:

@valid_attrs %{email: "some email", password: "some password", username: "some username"}


def user_fixture(attrs \\ %{}) do
  {:ok, user} =
    attrs
    |> Enum.into(@valid_attrs)
    |> Accounts.create_user()

  user
end

...

test "get_user!/1 returns the user with given id" do
  user = user_fixture()
  assert Accounts.get_user!(user.id) == user
end

Btw, get_user is straight from generator: def get_user!(id), do: Repo.get!(User, id)

What is the proper way to test virtual field?