Add tests for snowpack babel plugin.

[yukukotani]

Resolve #155.

Add tests for babel-plugin in __tests__/babel-plugin.
I'm not sure about directory structure and naming. Please give me some advice!

Details

runner.js find test files that end with .test.json.
*.test.json requires three keys. options is the option for babel plugin, input is the code before transpiled, and output is the code after transpiled.

[yukukotani]

package is reserved word (surprisingly!), so not working in strict mode.

[FredKSchott]

This is great! Thanks for tackling, @monchi. I'm having trouble leaving comments on a PR this big, so I'll just leave them here.

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Renaming/moving the entire integration directory has caused a lot of noise, so I went ahead and moved that myself in master. If you rebase this PR against master now, you should see a much cleaner diff/PR. If that causes any merge conflicts in tests/integration for you, you should be able to ignore them / just use master.

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Instead of building our own custom config/test data format, why don't we use the fixtures flow already supported by the util library? https://github.com/babel-utils/babel-plugin-tester#fixtures I'd rather just use their support/docs then having to manage our own data format as our tests grow.

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When I tested this locally, I saw that tests don't have names. We should find a way to grab the name from the options fixture. (probably supported automatically if we use their fixtures directory flow).

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Instead of installing a real dependency ("hyperapp") I'd recommend using a mocked out "example-dep" package in this test directory:

// Manually create node_modules/example-dep/package.json + test.cjs + test.mjs files
{
  "name": "example-dep",
  "version": "1.2.3",
  "main": "test.cjs",
  "module": "test.mjs"
}

You can also get rid of the package.json & package-lock.json files in the babel-plugin directory.

[yukukotani]

I'm having trouble leaving comments on a PR this big, so I'll just leave them here.

Thank you for reviewing, maybe you can leave comments on each commit page like fdac30f!

so I went ahead and moved that myself in master.

👍

Instead of building our own custom config/test data format, why don't we use the fixtures flow already supported by the util library?

Wow I didn't notice fixtures! Applied in bc6d8e6.

When I tested this locally, I saw that tests don't have names.

Resolved by using fixtures.

I'd recommend using a mocked out "example-dep" package in this test directory

Sounds good! Applied in 48a135b.

Also thank you for inviting me as a collaborator!

[FredKSchott]

LGTM!

Also thank you for inviting me as a collaborator!

Of course, thank you for your help maintaining & improving Snowpack for everyone!

[pika-ci]

🚀 This PR has been merged! Once a new release is created, any changes will become available on npm. Until then, you can load and install it directly from the Pika CDN:

npm install https://cdn.pika.dev/snowpack/master