Variables as values

[WVAviator]

Currently variables are defined as strings only.

There's no reason they couldn't be defined as values instead (provided the user doesn't try to expand them in the middle of a string). This could enable entire requests to be captured as variables, eliminating more repeat work.

suite: Recipe Test
variables:
  RECIPE_REQUEST:
    method: GET
    url: http://localhost:3000/recipes

tests:
  - test: Gets a recipe
    request: ${RECIPE_REQUEST}
    expect:
      status: 2xx

Initially, the deserialization would interpret the request as a Value::String("${RECIPE_REQUEST}"), and variable population could take in this Value and return a Value, and in this case take in a Value::String and return a Value::Object.

There would have to be handling of cases where more of a string is defined - what should happen, for example, if in this case the user tries to define `some_field: "Request info: ${RECIPE_REQUEST}" - ideally the app should never exit early, so this will need to be handled - perhaps by serializing the request object as JSON and inserting it into the string.