How to unit-test jq scripts?

[techhazard]

I'm writing several jq scripts, and I would like to add tests for those.

I have found the --run-tests argument that seems very useful, but it does not allow including other files (it assumes that's another test).

Here's what I expect to work

# myscript.jq
def rename_name_to_fullname:
  .fullname = .name | del(.name)
;

# myscript.test.jq
include "myscript" # <- this does not work, because it is interpreted as the program line of a test

# first test
rename_name_to_fullname  # program line
{ "name": "Jason Query"}    # input line
{ "fullname": "Jason Query"} # output line

Maybe the syntax for the include needs to be different in the test scripts, but I find the documentation of this testing setup to be very sparse in general.
Or is there another way to properly add tests?