.gitignore

node_modules
coverage
.nyc_output

package.json

{
  "name": "ava-nyc-bug",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "ava": {
    "files": [
      "src/**/*.test.js"
    ]
  },
  "scripts": {
    "test": "nyc --reporter=lcov ava --verbose && nyc report"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "ava": "^1.0.0-beta.7",
    "nyc": "^12.0.2"
  }
}

$ npm test

> ava-nyc-bug@1.0.0 test /Users/bret/repos/ava-nyc-bug
> nyc --reporter=lcov ava --verbose && nyc report

file:///Users/bret/repos/ava-nyc-bug/node_modules/chalk/index.js:2
const escapeStringRegexp = require('escape-string-regexp');

ReferenceError: require is not defined
    at file:///Users/bret/repos/ava-nyc-bug/node_modules/chalk/index.js:2:34
    at Generator.next (<anonymous>)
    at module.exports (file:///Users/bret/repos/ava-nyc-bug/node_modules/nyc/node_modules/default-require-extensions/js.js:8:9)
    at file:///Users/bret/repos/ava-nyc-bug/node_modules/nyc/node_modules/append-transform/index.js:62:4
npm ERR! Test failed.  See above for more details.

See avajs/ava#1904 for reference and more context.