Unable to set response body to "falsey" values

[mefellows]

Setting the response body directly to a null or false value results in an empty response from the mock server.

How to reproduce:

bundle exec bin/pact-mock-service service \
  --port 1234 \
  --consumer Foo \
  --provider Bar \
  --pact-specification-version 2 \
  --pact-dir ./tmp/pacts \
  --log ./tmp/bar_mock_service.log \
  --log-level DEBUG &
pid=$!

# Wait a few seconds, then register the interaction:

curl -X POST -H "X-Pact-Mock-Service: true"  localhost:1234/interactions -d '{
  "description": "foo",
  "request": {
    "path": "/foo",
    "method": "GET"
  },
  "response": {
    "status": 200,
    "headers": {
      "Content-Type": "application/json"
    },
    "body": null
  }
}'

# Test the response
curl localhost:1234/foo

I believe the render_body method is to blame, specifically this line which checks for a falsey value of the body, meaning if the body is nil or false it returns an empty string.

I couldn't glean from the tests the exact behaviour as to why this statement existed in the first place, but my suspicion is that we need to be able to deal with the 'body not present' case to avoid returning null. However, this is presenting the explicit null / false case.

FWIW removing that line didn't cause in test failures, so perhaps we need to get some coverage on it.

See pact-foundation/pact-js#257 for background.

[bethesque]

This is tricky. What are you expecting the HTTP request to look like? null or false? How would you differentiate it from an empty body?

[mefellows]

This is tricky.

Indeed!

In this case, the body is a literal false. I think it could be differentiated because it would have the header Content-Length: 5. At least, that is the only way i can think of separating them.

[NiklasEi]

Any updates here? This issue makes it impossible to write pact tests for endpoints returning only a boolean.

[bethesque]

I've changed it to return '' if body.nil? and released the mock service. I have not done any testing on it. You'll need to get the pact client of whichever language you're using updated to the latest pact-ruby-standalone.

[mefellows]

Thanks Beth.

@NiklasEi what language are you using that needs it?

[NiklasEi]

Thanks for the update!

@NiklasEi what language are you using that needs it?

Javascript

[mefellows]

Yep, will get a new release out this week. Thanks