Why do my jest tests run locally, but not on Travis?

Question

I have a simple javascript project that is using ES6, plus import and export. Here is my .babelrc file

{
  "env": {
    "es": {
      "presets": [
        [
          "env",
          {
            "targets": {
              "browsers": ["last 2 versions"],
              "node": "current"
            },
            "modules": false
          }
        ]
      ],
      "ignore": ["**/*.test.js", "**/tests/*"]
    },
    "test": {
      "presets": ["env"]
    },
    "cjs": {
      "presets": [
        [
          "env",
          {
            "targets": {
              "browsers": ["last 2 versions"],
              "node": "current"
            }
          }
        ]
      ],
      "ignore": ["**/*.test.js", "**/tests/*"]
    }
  }
}

I run my tests with npm test, which runs this command out of my package.json: "test": "jest --notify".

Locally, everything runs fine and all my tests pass, but when I push to Travis, I get this error: SyntaxError: Unexpected token import. It does not recognize my import statements.

Here is my .travis.yml:

language: node_js
cache:
  yarn: true
node_js:
- '8.4'
script:
- npm test
env:
- NODE_ENV: feature/travis

Why is my .babelrc not working on Travis? What am I missing?

Answer 1

This is likely happening because you have defined NODE_ENV: feature/travis in your travis.yml. This will cause Travis to run your tests as NODE_ENV=feature/travis jest --notify.

This generally shouldn't cause concern, but jest will automatically set the NODE_ENV to test if it is not already set.

It could be that you're issue is similar to the discussion taking place over at https://github.com/facebook/jest/issues/3370. There is some contention on whether Jest should be automatically setting the NODE_ENV to test or if it should just use development if no NODE_ENV is present (or just respect whatever NODE_ENV is already set if its set globally).

You can also see this logic in the jest-cli https://github.com/facebook/jest/blob/master/packages/jest-cli/bin/jest.js#L12-L14

So my recommendation is to test this without having your NODE_ENV set in your travis.yml to see if it successfully runs all of your tests.