Tests for the generated output files/formats (Jest)

[didoo]

In the last week or so I have submitted a couple of PRs, and in both cases (especially in #121) I was afraid to have broken something without knowing. Of course, there are some tests, but if you look at this code for example:

style-dictionary/test/buildPlatform.js

Lines 127 to 131 in 1bdd60b

	var input = helpers.fileToJSON('./test/properties/nonPropertyNode.json');
	var output = helpers.fileToJSON('./test/output/output.json');
	assert.deepEqual(output.color.comment, input.color.comment);
	assert.deepEqual(output.color.base.comment, input.color.base.comment);
	assert.equal(output.color.base.attributes.comment, input.color.base.attributes.comment);

it's testing that the JSON in input and the resulting object in output have the same properties.
But what happens if during the refactoring I am introducing changes after in the pipeline, in the function that generates the output or in the template files? and this results in the generated files being different than expected? My suspect is that we don't know and we don't have tests in place to make us feel confident that the changes are not introducing regressions (at least this was my impression while working on the PRs).

Any ideas, thoughts, suggestions (or alternatives) about trying Jest (and its snapshots capabilities) to cover also the output/generated files?

[chazzmoney]

We could solve this by adding format/template tests that would ensure that the formats / templates are being generated as expected. That should give us end-to-end testing as per your suggestion.

Additionally, I like the idea of having one set of tests for generating the properties and another section of tests for generating output from those properties.

[didoo]

That's the reason why I implemented #107:

As soon as that PR will be merged, we'll be able to have reliable snapshot tests too :)

[chazzmoney]

We now have a usable structure in place for this. Just need to get all the tests set up the way we want.

[didoo]

Maybe we can close this one now?

[chazzmoney]

@didoo I was trying to decide if that was right. Is this done? Or is it only done once we have tests in place for every format?

[didoo]

In my initial comment, I was mainly referring to snapshot testing (which, for me, is the most important part, since SD is made to generate output files :) ). AFAIK we are covering all the formats with snapshots testing via __tests__/fomats/all.tests.js, no?

BTW in that file this test should be split:

style-dictionary/__tests__/formats/all.test.js

Line 76 in eba4970

it('should return ' + key + ' as a string', () => {

this test is for "should return [test] as a string", there should be another declaration for the snapshot ones (

style-dictionary/__tests__/formats/all.test.js

Line 80 in eba4970

expect(output).toMatchSnapshot();

). Is it OK if I do a PR tomorrow? Or it causes too many conflicts in the resulting tests with the open branches?

[chazzmoney]

You can make the branch and PR whenever. If you do it before we merge the sass map and example branches, you'll just have to do a pull / merge somewhere. Up to you whether you want to wait or do it now.

[didoo]

OK, I'll add it in my todo list then.

[chazzmoney]

Complete as of v2.7.0