Matt Beanland Posts - Answer Overflow

Matt Beanland

•Created by Matt Beanland on 5/24/2025 in #support

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.

5 replies

AEAsh Elixir

•Created by Matt Beanland on 5/21/2025 in #today-i-learned

_ in Integer, Float

iex> 1_000
1000
iex> 1_000.0
1000.0

iex> 1_000
1000
iex> 1_000.0
1000.0

1 replies

AEAsh Elixir

•Created by Matt Beanland on 5/21/2025 in #today-i-learned

Comparing Durations....

Wasn't today but have been working on adding :duration, Ash.Type.Duration to Ash as want it for my AshNeo4j datalayer, etc., and learned that while Durations can be added and subtracted, they aren't so easy to compare, particularly when larger inability to compare weeks and months without a reference instant. So we don't have a comparator on Durations, although durations small enough to convert to timeout (with Kernel to_timeout) can be. That said durations are really useful in expressions, in Ash we've added support so they can be added/subtracted from temporal types DateTime|Date|Time|NaiveDateTime which uses the respective shift, (subtract also uses Duration.negate()), with the result the same temporal type. Durations can be added and subtracted with result in duration. Durations can also be negated.

1 replies

AEAsh Elixir

•Created by Matt Beanland on 5/9/2025 in #support

Changeset truncates Time, DateTime and NaiveDateTime to whole seconds

Ash 3.5.8 is removing microseconds from Time, DateTime and NaiveDateTime, which I think is a bug. I've noticed this in a create changeset. For example ~U[2025-05-09 08:02:21.294214Z] is truncated to ~U[2025-05-09 08:02:21Z].

42 replies

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