Ash Elixir•2w ago

How to create a negative test for a verifier

Hi, I'm working on adding some verifiers to the transformer for the Ash Neo4j DataLayer, and I've got a simple Verifier that checks neo4j convention on the resource label Here is the verifier:

defmodule AshNeo4j.Verifiers.VerifyLabelCamelCase do
  @moduledoc "Verifies that the label is camelcase"
  use Spark.Dsl.Verifier

  alias Spark.Dsl.Verifier
  alias Spark.Error.DslError
  @regex ~r/^[A-Z][a-zA-Z]*$/

  @impl true
  def verify(dsl) do
    IO.inspect(dsl, label: :verify_label_camel_case_dsl)
    resource = Verifier.get_persisted(dsl, :module) |> IO.inspect(label: :resource)
    neo4j = Map.get(dsl, [:neo4j])
    label = Keyword.get(neo4j.opts, :label, nil) |> IO.inspect(label: :label)

    cond do
      label == nil ->
        {:error,
          DslError.exception(
            module: resource,
            message: "Label missing"
        )}

      Regex.match?(@regex, Atom.to_string(label)) ->
        :ok

      true ->
        {:error,
          DslError.exception(
            module: resource,
            message: "Label must be CamelCase"
          )}
    end
  end
end

defmodule AshNeo4j.Verifiers.VerifyLabelCamelCase do
  @moduledoc "Verifies that the label is camelcase"
  use Spark.Dsl.Verifier

  alias Spark.Dsl.Verifier
  alias Spark.Error.DslError
  @regex ~r/^[A-Z][a-zA-Z]*$/

  @impl true
  def verify(dsl) do
    IO.inspect(dsl, label: :verify_label_camel_case_dsl)
    resource = Verifier.get_persisted(dsl, :module) |> IO.inspect(label: :resource)
    neo4j = Map.get(dsl, [:neo4j])
    label = Keyword.get(neo4j.opts, :label, nil) |> IO.inspect(label: :label)

    cond do
      label == nil ->
        {:error,
          DslError.exception(
            module: resource,
            message: "Label missing"
        )}

      Regex.match?(@regex, Atom.to_string(label)) ->
        :ok

      true ->
        {:error,
          DslError.exception(
            module: resource,
            message: "Label must be CamelCase"
          )}
    end
  end
end

Here is an invalid resource, the neo4j (node) label for the InvalidLabel resource should be :Comment not :comment

  defmodule InvalidLabel do
    @moduledoc false
    use Ash.Resource,
      domain: AshNeo4j.Test.Domain,
      data_layer: AshNeo4j.DataLayer

    neo4j do
      label :comment
      store [:title]
      translate id: :uuid
    end

    attributes do
      uuid_primary_key :id
      attribute :title, :string, public?: true
    end
  end

  defmodule InvalidLabel do
    @moduledoc false
    use Ash.Resource,
      domain: AshNeo4j.Test.Domain,
      data_layer: AshNeo4j.DataLayer

    neo4j do
      label :comment
      store [:title]
      translate id: :uuid
    end

    attributes do
      uuid_primary_key :id
      attribute :title, :string, public?: true
    end
  end

I'm at a loss how to write a negative test, as the module simply doesn't compile. Ideally I'd like to delay compilation until in the unit test, and pass the test if it errors. Help appreciated.

Solution:

Define the module inside the test block

Jump to solution

3 Replies

Solution