How can I define test fixtures for jest.each in a separate file?

Question

In the eternal quest for sepation of concerns, I would like to rewrite my jest tests and move out all the data used for testing into a separate file. Example:

describe('something', () => {
    it.each`
        key       | value
        ${'foo'}  | ${{
            'this': ['is', 'a'],
            'long': ['js', 'object']
        }}
        ${'bar'}  | ${{
            'i': ['don\'t', 'want'],
            'all': ['this', 'stuff'],
            'in': ['my test file']
        }}
    `("should work as expected for '$key'", async ({key, value}) => {
        // Test logic goes here
        actual = doSomething(key)
        actual.shouldEqual(value)
    })
})

Instead, I would rather prefer to write something like this:

describe('something', () => {
    it.each('test/something-data.json', "should work as expected for '$key1'", async ({key1, key2}) => {
        // Test logic goes here
        actual = doSomething(key)
        actual.shouldEqual(value)
    })
})

And then would declare all my fixtures in a separate file test/something-data.json.

Is there any way to achieve at the moment in jest? Of course, I could read the fixtures manually from a file but this would not allow me to see single successes or failures for each fixture. Or would this be a future feature request for jest?

Answer 1

You can achieve it, you just need to require the json file

e.g.

it.each(
  require("./test/something-data.json")
)("should work as expected for '%s'",
  ({ key1, key2 }) => {
    // Test logic goes here
    expect(doSomething(key)).toEqual(value);
  }
);

working example