README.md

• Start Date: 2019-07-16
• RFC PR: (leave this empty, to be filled in later)
• Authors: Toru Nagashima (@mysticatea)

RuleTester supports processor

Summary

This RFC makes RuleTester class supporting processor option.

Motivation

Currently, we cannot test rules with processors. This is inconvenient for plugin rules which depend on processors. For example, vue/comment-directive rule could not use RuleTester to test.

Detailed Design

To add processor option and processorOptions (see #29) to test cases.

const { RuleTester } = require("eslint")
const rule = require("../../../lib/rules/example-rule")
const exampleProcessor = require("../../../lib/processors/example-processor")

const tester = new RuleTester()

tester.run("example-rule", rule, {
    valid: [
        {
            code: `
                <script>
                    console.log("Hello")
                </script>
            `,
            processor: exampleProcessor,
            processorOptions: {},
        },
    ],
    invalid: [],
})

§ processor option

This is a definition object of a processor that the "Processors in Plugins" section describes.

If this option was given, the tester applies the given processor to test code.

If the given processor didn't has supportsAutofix:true, the tester doesn't do autofix. Then if the test case had output option (except null) then the test case will fail.

§ processorOptions option

RFC #29 defines the processorOptions.

If this option was given along with processor option, it will be given to the processor.

Documentation

The RuleTester section should describe the new processor and processorOptions properties.

Drawbacks

It's a pretty rare case of a rule depends on the processor's behavior. I'm not sure if this feature is needed.

Backwards Compatibility Analysis

There are no concerns about breaking changes.

Related Discussions

• #25 (comment)