How to use files from plugin / blueprint repo in wp-cli blueprint step

I'm currently looking to implement a preview for one of our wp.org hosted plugins. In order to set up a meaningful demo we'd like to import some sample data using a wp-cli command. It looks like I can specify a wp-cli step, but I'm unsure what the execution context is of that command and what files it can access.

Ideally I'd be looking at providing this sort of structure in the SVN repo:

• assets
  • blueprints
    • blueprint.json
    • sample-replacements.csv

I tried referencing the file directly without any path information, as the example below, but that doesn't appear to work.

{
    "step": "wp-cli",
    "command": "wp say-what import sample-replacements.csv"
}

Is there a way to reference asset files in playground steps?

Start by tracing how the wp-cli step establishes its execution context and resolves files referenced by a blueprint. Compare that behavior with the proposed assets/blueprints/blueprint.json and sample-replacements.csv layout. Done means determining whether asset files can be referenced, or documenting the limitation and required supported behavior.