Jobs failing on Travis-CI build

Hi,
I am trying to build the package on travis-ci, but found that jobs on Intel failing for NO_ESLINT is failing. Detailed log is as below

$ git clone --depth=50 --branch=master https://github.com/kishorkunal-raj/babel-plugin-precompile-charcodes.git kishorkunal-raj/babel-plugin-precompile-charcodes
0.01s
Setting environment variables from .travis.yml
$ export NO_ESLINT=true
nvm.install
2.04s$ nvm install 0.12 2>install.err.log
cache.1
Setting up build cache
cache.npm
$ node --version
v0.12.18
$ npm --version
2.15.11
$ nvm --version
0.37.2
install.npm
202.56s$ npm install
9.86s$ [[ $NO_ESLINT == true ]] && npm run test-012 || npm test
> babel-plugin-precompile-charcodes@1.1.0 test-012 /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes
> nyc ava src/__tests__
Uncaught Exception: src/__tests__/index.js
TypeError: /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/src/__tests__/index.js: undefined is not a function
at Controller.__initialize (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/node_modules/estraverse/estraverse.js:377:34)
at Controller.traverse (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/node_modules/estraverse/estraverse.js:406:14)
at Object.traverse (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/node_modules/estraverse/estraverse.js:646:27)
at astDepth (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/node_modules/call-matcher/index.js:133:16)
at new CallMatcher (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/node_modules/call-matcher/index.js:38:33)
at /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/lib/babel-espower-visitor.js:14:16
at Array.map (native)
at new BabelEspowerVisitor (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/lib/babel-espower-visitor.js:11:35)
at PluginPass.visitor.Program (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/node_modules/babel-plugin-espower/lib/create-espower-visitor.js:16:38)
at newFn (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/visitors.js:276:21)
at NodePath._call (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/path/context.js:76:18)
at NodePath.call (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/path/context.js:48:17)
at NodePath.visit (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/path/context.js:105:12)
at TraversalContext.visitQueue (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/context.js:150:16)
at TraversalContext.visitSingle (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/context.js:108:19)
at TraversalContext.visit (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/babel-core/node_modules/babel-traverse/lib/context.js:192:19)
From previous event:
at Api._runWithoutPool (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/api.js:247:4)
at Api._run (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/api.js:170:20)
at /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/api.js:88:16
From previous event:
at Api.run (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/api.js:87:4)
at Object.exports.run (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/lib/cli.js:159:7)
at Object. (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/ava/cli.js:23:24)
at Module._compile (module.js:460:26)
at Module.replacementCompile (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/nyc/node_modules/append-transform/index.js:58:13)
at module.exports (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/nyc/node_modules/default-require-extensions/js.js:8:9)
at Object. (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/nyc/node_modules/append-transform/index.js:62:4)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.Module.runMain (module.js:501:10)
at Function.runMain (/home/travis/.node-spawn-wrap-5345-2fd712beeecf/node:40:10)
at Object. (/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/nyc/bin/wrap.js:23:4)
at Module._compile (module.js:460:26)
at Object.Module._extensions..js (module.js:478:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.Module.runMain (module.js:501:10)
at Object. (/home/travis/.node-spawn-wrap-5345-2fd712beeecf/node:140:8)
at Module._compile (module.js:460:26)
0 tests passed [04:37:30]
1 uncaught exception
----------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
----------|----------|----------|----------|----------|----------------|
All files | Unknown | Unknown | Unknown | Unknown | |
----------|----------|----------|----------|----------|----------------|
npm ERR! Linux 4.15.0-1077-gcp
npm ERR! argv "/home/travis/.nvm/versions/node/v0.12.18/bin/node" "/home/travis/.nvm/versions/node/v0.12.18/bin/npm" "run" "test-012"
npm ERR! node v0.12.18
npm ERR! npm v2.15.11
npm ERR! code ELIFECYCLE
npm ERR! babel-plugin-precompile-charcodes@1.1.0 test-012: `nyc ava src/__tests__`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the babel-plugin-precompile-charcodes@1.1.0 test-012 script 'nyc ava src/__tests__'.
npm ERR! This is most likely a problem with the babel-plugin-precompile-charcodes package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR! nyc ava src/__tests__
npm ERR! You can get information on how to open an issue for this project with:
npm ERR! npm bugs babel-plugin-precompile-charcodes
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!
npm ERR! npm owner ls babel-plugin-precompile-charcodes
npm ERR! There is likely additional logging output above.
npm ERR! Please include the following file with any support request:
npm ERR! /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/npm-debug.log
> babel-plugin-precompile-charcodes@1.1.0 pretest /home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes
> eslint src
/home/travis/build/kishorkunal-raj/babel-plugin-precompile-charcodes/node_modules/eslint/bin/eslint.js:16
const useStdIn = (process.argv.indexOf("--stdin") > -1),
^^^^^
SyntaxError: Use of const in strict mode.
at exports.runInThisContext (vm.js:73:16)
at Module._compile (module.js:443:25)
at Object.Module._extensions..js (module.js:478:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.Module.runMain (module.js:501:10)
at startup (node.js:129:16)
at node.js:814:3
npm ERR! Test failed. See above for more details.
The command "[[ $NO_ESLINT == true ]] && npm run test-012 || npm test" exited with 1.
cache.2
store build cache
Done. Your build exited with 1.

Start with the Travis configuration shown in the build log and src/__tests__/index.js, then reproduce the failure with npm run test-012 on Node 0.12. Investigate the reported estraverse and eslint errors in that environment. Done means the Intel Travis job completes successfully and the test command passes.

Written by the indexing model from the issue text.