feat: control which linefeed character to use (#45)

* docs: run doctoc

* docs: endOfLine

* feat: allow controlling endOfLine

* test: endOfLine

* refactor: use lf and crlf

* test: invalid value and no linefeed

* refactor: set default earlier, don't default input

Author: merceyz

Diff for: README.md

@@ -33,19 +33,45 @@ work with `mocha` and `jasmine`.
 <!-- START doctoc generated TOC please keep comment here to allow auto update -->
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 
-- [Installation](#installation)
-- [Usage](#usage)
-  - [import](#import)
-  - [Invoke](#invoke)
-  - [options](#options)
-  - [Test Objects](#test-objects)
-- [Examples](#examples)
-  - [Full Example + Docs](#full-example--docs)
-  - [Simple Example](#simple-example)
-- [Inspiration](#inspiration)
-- [Other Solutions](#other-solutions)
-- [Contributors](#contributors)
-- [LICENSE](#license)
+- [babel-plugin-tester](#babel-plugin-tester)
+  - [The problem](#the-problem)
+  - [This solution](#this-solution)
+  - [Installation](#installation)
+  - [Usage](#usage)
+    - [import](#import)
+    - [Invoke](#invoke)
+    - [options](#options)
+      - [plugin](#plugin)
+      - [pluginName](#pluginname)
+      - [pluginOptions](#pluginoptions)
+        - [babel.config.js](#babelconfigjs)
+      - [title](#title)
+      - [filename](#filename)
+      - [endOfLine](#endofline)
+      - [fixtures](#fixtures)
+      - [tests](#tests)
+      - [babel](#babel)
+      - [...rest](#rest)
+    - [Test Objects](#test-objects)
+      - [code](#code)
+      - [title](#title-1)
+      - [output](#output)
+      - [fixture](#fixture)
+      - [outputFixture](#outputfixture)
+      - [only](#only)
+      - [skip](#skip)
+      - [snapshot](#snapshot)
+      - [error](#error)
+      - [setup](#setup)
+      - [teardown](#teardown)
+      - [formatResult](#formatresult)
+  - [Examples](#examples)
+    - [Full Example + Docs](#full-example--docs)
+    - [Simple Example](#simple-example)
+  - [Inspiration](#inspiration)
+  - [Other Solutions](#other-solutions)
+  - [Contributors](#contributors)
+  - [LICENSE](#license)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
@@ -154,6 +180,17 @@ this value is `fixtures`. Test Object properties affected by this value are:
 absolute paths, then they will be `path.join`ed with `path.dirname` of the
 `filename`.
 
+#### endOfLine
+
+This is used to control which line endings the output from babel should have
+
+| Options    | Description                        |
+| ---------- | ---------------------------------- |
+| `lf`       | Unix - default                     |
+| `crlf`     | Windows                            |
+| `auto`     | Use the system default             |
+| `preserve` | Use the line ending from the input |
+
 #### fixtures
 
 This is a path to a directory with this format:

Diff for: src/__tests__/index.js

@@ -1,6 +1,7 @@
 import fs from 'fs'
 import path from 'path'
 import assert from 'assert'
+import {EOL} from 'os'
 // eslint-disable-next-line import/default
 import pluginTester from '../'
 import identifierReversePlugin from './helpers/identifier-reverse-plugin'
@@ -708,6 +709,105 @@ test('appends to root plugins array', async () => {
   expect(programVisitor).toHaveBeenCalledTimes(9)
 })
 
+test('endOfLine - default', async () => {
+  await runPluginTester(
+    getOptions({
+      tests: [
+        {
+          code: 'var foo = "";\nvar bar = "";',
+          output: 'var foo = "";\nvar bar = "";',
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - Unix', async () => {
+  await runPluginTester(
+    getOptions({
+      endOfLine: 'lf',
+      tests: [
+        {
+          code: 'var foo = "";\nvar bar = "";',
+          output: 'var foo = "";\nvar bar = "";',
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - Windows', async () => {
+  await runPluginTester(
+    getOptions({
+      endOfLine: 'crlf',
+      tests: [
+        {
+          code: 'var foo = "";\nvar bar = "";',
+          output: 'var foo = "";\r\nvar bar = "";',
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - auto', async () => {
+  await runPluginTester(
+    getOptions({
+      endOfLine: 'auto',
+      tests: [
+        {
+          code: 'var foo = "";\nvar bar = "";',
+          output: `var foo = "";${EOL}var bar = "";`,
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - preserve', async () => {
+  await runPluginTester(
+    getOptions({
+      endOfLine: 'preserve',
+      tests: [
+        {
+          code: 'var foo = "";\r\nvar bar = "";',
+          output: `var foo = "";\r\nvar bar = "";`,
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - preserve - no linefeed', async () => {
+  await runPluginTester(
+    getOptions({
+      endOfLine: 'preserve',
+      tests: [
+        {
+          code: 'var foo = "";',
+          output: 'var foo = "";',
+        },
+      ],
+    }),
+  )
+})
+
+test('endOfLine - invalid option', async () => {
+  const errorThrown = await runPluginTester(
+    getOptions({
+      endOfLine: 'invalid',
+      tests: [
+        {
+          code: 'var foo = "";',
+          output: 'var foo = "";',
+        },
+      ],
+    }),
+  ).catch(e => e)
+
+  expect(errorThrown.message).toBe("Invalid 'endOfLine' value")
+})
+
 function getOptions(overrides) {
   return {
     pluginName: 'captains-log',

Diff for: src/index.js

@@ -3,6 +3,7 @@
 import assert from 'assert'
 import path from 'path'
 import fs from 'fs'
+import {EOL} from 'os'
 import pathExists from 'path-exists'
 import mergeWith from 'lodash.mergewith'
 import invariant from 'invariant'
@@ -39,6 +40,7 @@ function pluginTester({
   fixtures,
   fixtureOutputName = 'output',
   filename,
+  endOfLine = 'lf',
   ...rest
 } = {}) {
   let testNumber = 1
@@ -52,6 +54,7 @@ function pluginTester({
       fixtureOutputName,
       filename,
       babel,
+      endOfLine,
       ...rest,
     })
   }
@@ -144,7 +147,13 @@ function pluginTester({
         let errored = false
 
         try {
-          result = formatResult(babel.transform(code, babelOptions).code)
+          result = formatResult(
+            fixLineEndings(
+              babel.transform(code, babelOptions).code,
+              endOfLine,
+              code,
+            ),
+          )
         } catch (err) {
           if (error) {
             errored = true
@@ -214,6 +223,34 @@ function pluginTester({
   }
 }
 
+function fixLineEndings(code, endOfLine, input) {
+  return code.replace(/\r?\n/g, getReplacement())
+
+  function getReplacement() {
+    switch (endOfLine) {
+      case 'lf': {
+        return '\n'
+      }
+      case 'crlf': {
+        return '\r\n'
+      }
+      case 'auto': {
+        return EOL
+      }
+      case 'preserve': {
+        const match = input.match(/\r?\n/)
+        if (match === null) {
+          return EOL
+        }
+        return match[0]
+      }
+      default: {
+        throw new Error("Invalid 'endOfLine' value")
+      }
+    }
+  }
+}
+
 const createFixtureTests = (fixturesDir, options) => {
   if (!fs.statSync(fixturesDir).isDirectory()) return
 
@@ -259,6 +296,7 @@ const createFixtureTests = (fixturesDir, options) => {
         pluginOptions,
         fixtureOutputName,
         babel,
+        endOfLine,
         formatResult = r => r,
         ...rest
       } = options
@@ -288,8 +326,15 @@ const createFixtureTests = (fixturesDir, options) => {
         rest,
         mergeCustomizer,
       )
+
+      const input = fs.readFileSync(codePath).toString()
       const actual = formatResult(
-        babel.transformFileSync(codePath, babelOptions).code,
+        fixLineEndings(
+          babel.transformSync(input, {...babelOptions, filename: codePath})
+            .code,
+          endOfLine,
+          input,
+        ),
       )
 
       const outputPath = path.join(fixtureDir, `${fixtureOutputName}${ext}`)