Error: Unable to call `file`

[joanrivera]

Describe the bug
I try the code in the section Sending files and form data but it fail with Error: Unable to call `file`, which is undefined or falsey

To Reproduce

1. Copy the sample code in Sending files and form data to a file sendfiles.yml
2. Create a dummy file and update the respective path in sendfiles.yml: echo 'test content' > test.txt
3. Execute Strest: strest sendfiles.yml

Return

[ Strest ] Found 1 test file(s)
[ Strest ] Schema validation: 1 of 1 file(s) passed

✖ Testing postwithfile failed (0.007s)
[ Validation ] Failed to process postwithfile request line using nunjucks:
 Template render error: (unknown path) [Line 9, Column 26]
  Error: Unable to call `file`, which is undefined or falsey

Response:
null
[ Strest ] Failed before finishing all requests

Additional context

• Strest installation: npm i -g @strest/cli
• node --version: v8.10.0

[bruehldev]

Same here, turns out the commit #141 is not part of the latest release yet.
Building the master with the the commit #141 leads to following JS Error: UnhandledPromiseRejectionWarning: TypeError [ERR_INVALID_ARG_TYPE]: The first argument must be one of type string, Buffer, ArrayBuffer, Array, or Array-like Object. Received type object
at Function.from (buffer.js:305:9)
at FormData.getBuffer ...