https://github.com/benoitzugmeyer/babel-plugin-test-export

Export private variables and functions to your tests
https://github.com/benoitzugmeyer/babel-plugin-test-export

Last synced: 4 months ago
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Export private variables and functions to your tests

• Host: GitHub
• URL: https://github.com/benoitzugmeyer/babel-plugin-test-export
• Owner: BenoitZugmeyer
• License: isc
• Created: 2016-12-18T19:18:16.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2018-06-16T20:24:40.000Z (over 6 years ago)
• Last Synced: 2024-10-03T09:17:04.447Z (4 months ago)
• Language: JavaScript
• Size: 96.7 KB
• Stars: 4
• Watchers: 2
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# babel-plugin-test-export

[![Build Status](https://travis-ci.org/BenoitZugmeyer/babel-plugin-test-export.svg?branch=master)](https://travis-ci.org/BenoitZugmeyer/babel-plugin-test-export)

Export private variables and functions to your tests. Annotate variable and function declarations

with a `// @test-export` comment and they will be exported in a `__test__` property of the module.

Use values exported like this to write more focused tests or to mock things.

## Install

```

$ yarn add --dev babel-plugin-test-export

```

Make sure to add this plugin only for tests. Example, in your `.babelrc`:

```js

{

  // ... your common configuration ...

  env: {

    test: {

      plugins: [ "test-export" ]

    }

  }

}

```

## Example

`mylib.js`:

```js

// @test-export

function appendFoo(str) {

    return str + "foo"

}

module.exports = function (str) {

    return appendFoo(str).toUpperCase()

}

```

`mylibSpec.js` (`jasmine` example):

```js

const mylib = require("./mylib")

// Test private functions!

describe("appendFoo", () => {

    const { appendFoo } = mylib.__test__

    it("appends foo", () => {

        expect(appendFoo("a")).toBe("afoo")

    })

})

// Mock private functions!

describe("mylib", () => {

    it("appends foo and turn value in uppercase", () => {

        spyOn(mylib.__test__, "appendFoo")

        expect(mylib("a")).toBe("AFOO")

        expect(mylib.__test__.appendFoo).toHaveBeenCalled()

    })

})

```

## How it works

All references of the annotated variables and functions are rewritten to use the exported reference

instead.  The above example is rewritten as:

```js

const __test__ = {};

// @test-export

__test__.appendFoo = function appendFoo(str) {

    return str + "foo";

};

module.exports = function (str) {

    return (void 0, __test__.appendFoo)(str).toUpperCase();

};

module.exports.__test__ = __test__

```

## Drawbacks

* Currently, it only works with commonjs exported modules.

* Function and variable declarations are not hoisted anymore, so make sure to always write

  declarations before using them.

## Inspiration and thanks

I used [babel-strip-test-code](https://github.com/madole/babel-strip-test-code) as a start to write

this plugin.  Its goal is quite similar: export private values via a `export __test__ = { ... }` and

it will strip this export for you in production.  This approach, while quite simpler than mine,

is a bit more verbose and doesn't allow mocks.