How do I access a child entity field for reference in an MFTF Test

Question

I need assistance trying to access a field of a required entity inside a parent entity created for a test

Example I am trying to create a configurable product

<createData entity="productAttributeWithTwoOptions" stepKey="createConfigProductAttributes">

The entity for that looks like this

<entity name="productAttributeWithTwoOptions" type="ProductAttribute">
  <data key="attribute_code" unique="suffix">attribute</data>
  <data key="frontend_input">select</data>
  ...
  <data key="used_for_sort_by">true</data>
  <requiredEntity type="FrontendLabel">ProductAttributeFrontendLabel</requiredEntity>
</entity>

In the test how could I access the label field from the FrontendLabel required entity?

<entity name="ProductAttributeFrontendLabel" type="FrontendLabel">
  <data key="store_id">0</data>
  <data key="label" unique="suffix">attribute</data>
</entity>

I assumed it might be something like this {{createConfigProductAttributes.ProductAttributeFrontendLabel.label}}

Answer 1

Using XDebug with Codeception https://devdocs.magento.com/mftf/docs/debugging.html I was able to see what the generated data entities looked like.

MFTF flattens the data returned by the createData action and so I was able to access the data needed by referencing it like this

$createConfigProductAttributeWithTwoOptions.attribute[frontend_labels][0][label]$