(ArgumentError) argument error - when trying to pass a list of values to a changeset

Phoenix Forum Questions / Help
,
1

Hi all

I am trying to pass a list of values to a changeset and have following methods:

def changeset_all(model, list) when is_list(list) do

		list
		|> Enum.map(fn param -> changeset(model, param) end)

  end


  def changeset(model, params \\ %{}) do

		model
    |> cast(params, [:code, :en, :de, :it, :fr])
    |> validate_required([:code, :en])
    |> validate_length(:code, max: 2)
    |> unique_constraint(:code)

  end

I wrote a test

@valid_attrs_list [ %{code: "CH", en: "Switzerland", de: "Schweiz", it: "Svizzera", fr: "Suisse"},
										  %{code: "IT", en: "Italy", de: "Italien"},
										  %{code: "FR", en: "Franche", de: "Frankreich"} ]

test "a valid list of countries" do
  changeset = Country.changeset_all(%Country{}, @valid_attrs_list)
  assert changeset.valid?
end

The compiler complains:

 1) test a valid list of countries (Pubcus.CountryModelTest)
     test/models/country_model_test.exs:27
     ** (ArgumentError) argument error
     stacktrace:
       :erlang.apply([#Ecto.Changeset<action: nil, changes: %{code: "CH", de: "Schweiz", en: "Switzerland", fr: "Suisse", it: "Svizzera"}, errors: [], data: #Pubcus.Country<>, valid?: true>], :valid?, [])

What am I doing wrong?

The schema definition:

schema "countries" do

    field :code, :string
    field :en, :string
    field :de, :string
    field :it, :string
    field :fr, :string

    timestamps

  end

Thanks

1 Like
2

What do you intend your changeset_all function to do? I don’t quite get your intent here.

3

I want to pass a list of countries to changeset not only one country.
The changeset function should validate, if all passes value is valid or not.

4

Yeah, well I figured that you may want to do that but:

  1. You write a function in code of your app that is to be used only in tests. This is not great to pollute your app like that. Shame on you, really :wink:

  2. You are destroying the readability of your test cases. You have just few values that can be valid, just add X examples of tests or test those one by one in the same test case.

5

@hubertlepicki So I want to test a list of countries and have to idea how to do it?
What is your suggestion?

Here is the whole code:

defmodule Pubcus.Country do

	use Pubcus.Web, :model

  schema "countries" do

    field :code, :string
    field :en, :string
    field :de, :string
    field :it, :string
    field :fr, :string

    timestamps

  end

  def changeset_all(model, list) when is_list(list) do

		list
		|> Enum.map(fn param -> changeset(model, param) end)

  end


  def changeset(model, params \\ %{}) do

		model
    |> cast(params, [:code, :en, :de, :it, :fr])
    |> validate_required([:code, :en])
    |> validate_length(:code, max: 2)
    |> unique_constraint(:code)

  end


end

and the tests

defmodule Pubcus.CountryModelTest do

  use Pubcus.ModelCase

  alias Pubcus.Country

  @valid_attrs %{ code: "CH", en: "Switzerland", de: "Schweiz", it: "Svizzera", fr: "Suisse" }
  @invalid_attrs %{ code: "CHH" }

  @valid_attrs_list [ %{code: "CH", en: "Switzerland", de: "Schweiz", it: "Svizzera", fr: "Suisse"},
                      %{code: "IT", en: "Italy", de: "Italien"},
                      %{code: "FR", en: "Franche", de: "Frankreich"} ]

  test "a valid dataset" do

    changeset = Country.changeset(%Country{}, @valid_attrs)
    assert changeset.valid?

  end

  test "a invalid country code" do

    errors = errors_on(%Country{}, @invalid_attrs)
    assert {:code, "should be at most 2 character(s)"} in errors
    assert {:en, "can't be blank"} in errors

  end

  test "a valid list of countries" do

    changeset = Country.changeset_all(%Country{}, @valid_attrs_list)
    assert changeset.valid?

  end


end

Thanks

6

Why it is wrong to test a list of countries?

7

It looks like you’re trying to call valid? on a list of changesets. I believe you need to do something like this:

changesets = Country.changeset_all(%Country{}, @valid_attrs_list)
Enum.each(changesets, &(assert(&1.valid?)))

Or this:

Enum.each(@valid_attrs_list, fn(valid_attrs) ->
  changeset = Country.changeset(%Country{}, valid_attrs)
  assert(changeset.valid?)
end)
1 Like
8

thanks so much.