We are using sed and envsubst to render templates in the scenario tests. Both have issues. sed patterns can be a challenge to write cleanly for complex file formats. envsubst makes it complicated to embed non-template text with $, such as might appear in hash values.

We should look at other options. We could adopt an existing tool like https://docs.gomplate.ca or jinja2, or we could build a little tool that just does what we need.