Newman: api tests run well on Postman, but has error "Encountered an error during JSON.parse(): Unexpected token" through Newman.

[fantagaro]

We have tests that run well on Postman, but got error "Encountered an error during JSON.parse(): Unexpected token" run through Newman.

Same JSON.parse() works fine in other api tests. Only 3 api tests failed on JSON.parse(). The only difference about these api endpoints were these 3 endpoints used to return text/html before. We recently changed it to application/json, so that all of the tests are passed after JSON.parse(responseBody). But the error "Encountered an error during JSON.parse(): Unexpected token" prevent part of the tests to run through Newman.

Please advice. Thanks!

[abhijitkane]

@fantagaro What version of Newman are you using? You can use newman -V.

Also, can you attach a screenshot of your command line?

[fantagaro]

2.1.2

Which part of command line? We export the test collection to json file and run by Newman in Jenkins.

[shamasis]

@fantagaro - you mind trying out some basic debugging first?

Can you put each json.parse in try catch block and log the errors?

var responseJSON;

try {
    responseJSON = JSON.parse(responseBody);
catch (err) {
    console.log(err);
}

[shamasis]

Also log the responseBody in those cases.

[fantagaro]

I replaced responseJSON = JSON.parse(responseBody); to
try {
responseJSON = JSON.parse(responseBody);
catch (err) {
console.log(err);
console.log(responseBody);
}

In the Jenkins console log, I got "Unexpected token catch" instead of "Encountered an error during JSON.parse(): Unexpected token". No other info prints out.

[fantagaro]

[elssar]

Hi @fantagaro,

There is a typo in the code snippet, its missing closing braces for the try block

Try this instead

try {
    responseJSON = JSON.parse(responseBody);
}
catch (err) {
    console.log(err);
    console.log(responseBody);
}

[fantagaro]

Thanks @elssar!
Here's the new error message:

[fantagaro]

So looks like Newman has trouble with the params in the URL.

[czardoz]

@fantagaro can you add a console.log(responseBody) at the top of your test script, and paste the output here?

[fantagaro]

@czardoz Added console.log(responseBody); to the top of the test script and attached the result.

[fantagaro]

Thanks for looking into it! @czardoz

[fantagaro]

Hi @czardoz we tested locally using newman, same error.
Here's the command line:
clone the repo
npm install
npm run test-mobile-sdk-production

[fantagaro]

@abhijitkane thanks for logging the bug, and look forward to solutions. Thanks!

[shamasis]

We could not replicate this issue. It would be best if you can mail us at [email protected]. We might need additional information to debug this and they might not be shareable in public forum.

Also, before mailing, you may try running this collection in latest Newman v3. Newman v3 provides a better stack trace for debugging your error.

Closing this issue here.

[fantagaro]

My coworker sent an email to [email protected] and the issue has been solved!

[shamasis]

Thank you. Would you be able to summarise the solution here? Would help others when the stumble over this issue. 😊

[suhasgaddam]

I work with @fantagaro and emailed [email protected].

@czardoz noticed there was an extra character at the beginning of our api response. The character turned out to be the BOM. After removing the stray BOM, node is able to successfully call JSON.parse.

Confirmed the issue with:

curl --silent $URL | hexdump -C and the first bytes were 0xEF 0xBB 0xBF

Sidenote:
JSON.parse implementations are not required to ignore the presence of BOM.

If I read

In the interests of interoperability, implementations
   that parse JSON texts MAY ignore the presence of a byte order mark
   rather than treating it as an error.

from https://tools.ietf.org/html/rfc7159 correctly.

[shamasis]

We are working on a variant that does the same. :-)

[mesmitpatel]

Hey, I'm facing a similar issue.
Tests did run successfully but console shows error for this one particular request only.
Although this problem goes away if I send JSON instead of plain text.