fixture-injection
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    0.3.2 • Public • Published

    fixture-injection

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    Note: fixture-injection is still in alpha stage.

    fixture-injection is a test helper tool for Jest and Jasmine to define and use fixtures easily by leveraging dependency injection.

    Fixtures are code that sets up test subjects and the testing environment defined as a value or a function. These fixtures can be injected to beforeAll(), it(), test(), etc. as arguments.

    Usage

    tests/__fixtures__.js:

    // Example 1) Simple value
    const foo = 'FOO'
     
    // Example 2) Fixture function to provide a value which requires another fixture `foo`
    const bar = (foo) => `BAR(${foo})`
     
    // Example 3) Asynchronous fixture function to provide a value
    const baz = async (provide, bar) => { // requires another fixture `bar`
      // Write setup code here
      await provide(`BAZ(${bar}`) // provide the value
      // `await` above waits until the context (test case or suite) finishes
      // Write teardown code here
    }
     
    module.exports = {
      foo,
      bar,
      baz
    }

    example.spec.js:

    describe('My test suite', () => {
      let fixtures = {}
     
      beforeAll((foo) => { // Inject fixtures to *a suite* by beforeAll()
        fixtures.foo = foo
      })
     
      test('with fixtures', (bar, baz) => { // Inject fixtures to *a test case*
        // bar and baz are initialized just before this block
        const { foo } = fixtures // Get fixtures from the suite
     
        expect(foo).toEqual('FOO')
        expect(bar).toEqual('BAR(FOO)')
        expect(baz).toEqual('BAZ(BAR(FOO))')
     
        // bar and baz are released just after this block
      })
     
      // foo is released by hidden afterAll() of this block automatically
    })

    Features

    1. The code in the fixture function can do whatever you want
    2. Fixture function can be asynchronous and can have setup and teardown code around await provide()
    3. Fixtures are also available in other fixtures, and the dependencies are automatically resolved
      • Asynchronous fixtures are initialized concurrently as much as possible
    4. Local fixtures are initialized every time in each injected context
    5. Global fixtures are singletons and initialized only once
      • [Jest] They are initialized by Jest runner and will be sent to individual test workers via IPC
    6. In-line fixtures are also available by fixture() in each test file

    Packages

    Install/Setup

    See the documentation of each test framework extension.

    Related Work

    • pytest
      • pytest is a popular testing framework for Python. fixture-injection was inspired by its fixtures. pytest fixture has a scope (session/module/function) to manage its lifecycle and can be a generator to have setup/teardown logic in it.

    Install

    npm i fixture-injection

    DownloadsWeekly Downloads

    2

    Version

    0.3.2

    License

    MIT

    Unpacked Size

    95.5 kB

    Total Files

    7

    Last publish

    Collaborators

    • yatsu