Allow sequence in attributes passed to `insert_list` about ex_machina HOT 5 CLOSED

ah, ok.
I was able to get everything working with this:

mythings =
  insert_list(mything_count, :mything,
    name: fn -> sequence(:name, &"Custom-Name-#{&1}") end
  )

def mything_factory(attrs) do
  name = Map.get(attrs, :name, sequence("Test-Thing"))

  %MyThing{
    name: name,
  }
  |> merge_attributes(attrs)
  |> evaluate_lazy_attributes()
end

Thanks for your help!

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Hi @kevinkirkup, do you have any more information you can provide? Can you share your factory setup and your test setup?

Just looking at the error, it seems like for some reason, it doesn't get that the second argument to sequence/2 is a function:

** (BadFunctionError) expected a function, got: "Custom-Name-"

But name: sequence(:name, &"Custom-Name-#{&1}") should be a valid sequence. I tested that in the ExMachina tests and it works.

Usually, I'd use sequences in the factory definition, not when calling insert. Are you calling the insert_list/3 function in a test or inside the factory? Do you get a different result if you try inside the factory?

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Hi @germsvel, here is the factory definition:

  def myFactory_factory(attrs) do
    %MyFactory{
      name: sequence("Test-MyFactory"),
    }
    |> merge_attributes(attrs)
  end

I'm calling insert_list/3 as part of the test setup.
Yeah, I've seen the main pattern is to use sequence in the factory, but in this case, the name has to be formatted a certain way for the test case.

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I updated the factory and now I'm seeing a different behavior.

Changed the factory to:

  def myFactory_factory(attrs) do
    name = Map.get(attrs, :name, sequence("Test-MyFactory"))
    %MyFactory{
      name: name,
    }
    |> merge_attributes(attrs)
  end

     test/xxx_web/controllers/myfactory_controller_test.exs:42
     ** (Ecto.ConstraintError) constraint error when attempting to insert struct:

         * myfactory_id_name_index (unique_constraint)

     If you would like to stop this constraint violation from raising an
     exception and instead add it as an error to your changeset, please
     call `unique_constraint/3` on your changeset with the constraint
     `:name` as an option.

     The changeset has not defined any constraint.

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@kevinkirkup for the last error (the unique constraint one) are you passing a sequence when calling insert?

In other words, are you still calling this in your test?

myList = insert_list(8, :myFactory, name: sequence(:name, &"Custom-Name-#{&1}"))

If so, the error is happening because you're generating the sequence first, and then passing that generated value into insert_list/3, which means all 8 of your records have the same name. In other words, this is the equivalent of what you're doing:

# generates a name
name = sequence(:name, &"Custom-Name-#{&1}")
# e.g. => "Custom-Name-1"

# passes that name to all 8 factories
myList = insert_list(8, :myFactory, name: name)

In order to get around that you can delay the evaluation of attributes by passing a function:

myList = insert_list(8, :myFactory, name: fn -> sequence(:name, &"Custom-Name-#{&1}") end)

All in all, I'd expect the code to look something like this:

# factory.ex
def myFactory_factory(attrs) do
    %MyFactory{
     # the default sequence
      name: sequence("some name")
    }
end

# some_test.exs
test "I can do something" do
  # overriding the name attribute
  a = insert_list(8, :myFactory, name: fn -> sequence(:name, &"Custom-Name-#{&1}") end)
end

That should solve your unique constraint error.

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