Learning JEST w Vue.js : error on forst example test - vue.js

Question

I am trying to learn JEST for testing my Vue apps..
I started discovering it by running a standard vue-cli (3) example, with full config ( babel, lint, vuex, vue-router, unit and e2e tests)
vue create cli-test
generated package.json
"eslintConfig": {
"root": true,
"env": {
"node": true
},
"extends": [
"plugin:vue/essential",
"#vue/prettier"
],
"rules": {},
"parserOptions": {
"parser": "babel-eslint"
}
},
"postcss": {
"plugins": {
"autoprefixer": {}
}
},
"browserslist": [
"> 1%",
"last 2 versions",
"not ie <= 8"
],
"jest": {
"moduleFileExtensions": [
"js",
"jsx",
"json",
"vue"
],
"transform": {
"^.+\\.vue$": "vue-jest",
".+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$": "jest-transform-stub",
"^.+\\.jsx?$": "babel-jest"
},
"moduleNameMapper": {
"^#/(.*)$": "<rootDir>/src/$1"
},
"snapshotSerializers": [
"jest-serializer-vue"
],
"testMatch": [
"**/tests/unit/**/*.spec.(js|jsx|ts|tsx)|**/__tests__/*.(js|jsx|ts|tsx)"
],
"testURL": "http://localhost/"
}
I run lint wo any error
yarn lint
then I run test:unit, with an error on the import statement in the only generated spec file tests/unit/HelloWorld.spec.js
yarn run test:unit
yarn run v1.9.2
$ vue-cli-service test:unit
FAIL tests/unit/HelloWorld.spec.js
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
/Users/yves/Developments/WIP/TESTS/cli-test/tests/unit/HelloWorld.spec.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import "core-js/modules/es6.array.iterator";
^^^^^^
SyntaxError: Unexpected token import
at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:403:17)
Test Suites: 1 failed, 1 total
Tests: 0 total
Snapshots: 0 total
Time: 5.532s
Ran all test suites.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
why this generated test does not pass ? should not it be ielf checked before being autogenerated ? too bad start for learning ... or being optimist, this error is raised to challenge immediatly the newbie ...

Answer 1

need to upgrade babel-jest
yarn upgrade babel-jest#23.4.0"
then test:uniy passed
yarn run test:unit
yarn run v1.9.2
$ vue-cli-service test:unit
PASS tests/unit/HelloWorld.spec.js
HelloWorld.vue
✓ renders props.msg when passed (30ms)
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 7.349s
Ran all test suites.