how to fix 'error from lcovParse: ' 'Failed to parse string'? on circleICI v2.0 using coveralls with mocha

circleCI fails when it tries to run this command:

#!/bin/bash --login
cat ./coverage/coverage.json | ./node_modules/.bin/adana --format lcov | ./node_modules/coveralls/bin/coveralls.js

[error] "2019-02-20T20:22:50.695Z"  'error from lcovParse: ' 'Failed to parse string'
[error] "2019-02-20T20:22:50.697Z"  'input: ' '\n'
[error] "2019-02-20T20:22:50.697Z"  'error from convertLcovToCoveralls'

/home/ubuntu/Band-of-Coders/uber-auth/node_modules/coveralls/bin/coveralls.js:18
        throw err;
        ^
Failed to parse string
Exited with code 1

this it is how I run my tests:

./node_modules/.bin/_mocha -r test/helper/chai.js -r adana-dump --compilers js:babel-core/register -R spec --recursive --slow 100 test/spec/**/*.spec.js

In my .circleci/config.yml, I have:

 - run: npm test
 - run: npm install coveralls
 - run: cat ./coverage/coverage.json | ./node_modules/.bin/adana --format lcov | ./node_modules/coveralls/bin/coveralls.js

any thoughts about why this is happening? I really appreciate any help

Solution

You might need to make use of nyc with babel-plugin-istanbul or plain istanbul to generate the coverage data first before you run your coverage reporting script. Otherwise, there'd be no data available to generate a report.

I've used nyc with babel-plugin-istanbul before and got expected results.

"test": "NODE_ENV=test nyc ./node_modules/.bin/_mocha <your-test-matching-wildcard-here>",
"coveralls": "NODE_ENV=test nyc report --reporter=text-lcov | coveralls"

You'll also need to have some configuration in your .nycrc:

{
  "reporter"   : ["text", "text-summary", "lcov", "html"],
  "include"    : ["<your-include-wildcard>"],
  "exclude"    : ["<your-exclude-wildcard>"],
  "require"    : ["@babel/register"],
  "sourceMap"  : false,
  "instrument" : false,
  "all"        : true
}

Run test script first then coveralls.