Added "--compare"

docs/index.html

@@ -110,7 +110,17 @@ <h1>Command-line usage</h1>
 				<p>Alternatively, you may overwrite the original files by specifying <mark>--replace</mark> or <mark>-r</mark> parameter.</p>
 				<code>stylus-supremacy format ./path/to/your/file.styl --replace</code>
 
-				<p>Note that <mark>--outDir</mark> and <mark>--replace</mark> do not work together. You have to choose just one.</p>
+				<p>In case you want to check whether your file is being formatted correctly, you may specify <mark>--compare</mark> or <mark>-c</mark>. If the input file does not comply with the given formatting options, the command will print out the difference and exit with a code of 1. This is useful when running in a CI environment.</p>
+				<code>
+					stylus-supremacy format ./path/to/your/file.styl --compare<br>
+					The first mismatched was at line 2.<br>
+					&nbsp;&nbsp;Actual: →display none<br>
+					&nbsp;&nbsp;Expect: →display: none;<br>
+					&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;^^^^^^^<br>
+				  	Done with 1 error.
+				</code>
+
+				<p>Note that <mark>--outDir</mark>, <mark>--replace</mark>, and <mark>--compare</mark> do not work together. You have to choose just one.</p>
 			</article>
 			<article id="programming">
 				<h1>Programming usage</h1>

edge/commandLineProcessor.js

@@ -10,6 +10,7 @@ const format = require('./format')
 const createFormattingOptions = require('./createFormattingOptions')
 const createFormattingOptionsFromStylint = require('./createFormattingOptionsFromStylint')
 const checkIfFilePathIsIgnored = require('./checkIfFilePathIsIgnored')
+const compareContent = require('./compareContent')
 
 function process(command, params = [], Console = console) {
 	if (command === '--version' || command === '-v') {
@@ -19,6 +20,7 @@ function process(command, params = [], Console = console) {
 		const optionFilePathParams = getParam(params, ['--options', '-p'], 1)
 		const outputDirectoryParams = getParam(params, ['--outDir', '-o'], 1)
 		const replaceOriginalParams = getParam(params, ['--replace', '-r'])
+		const compareOriginalParams = getParam(params, ['--compare', '-c'])
 		const dryRunParams = getParam(params, ['--dryRun'])
 		const debuggingParams = getParam(params, ['--debug', '-d'])
 
@@ -90,6 +92,13 @@ function process(command, params = [], Console = console) {
 							fs.writeFileSync(path, outputContent)
 						}
 
+					} else if (compareOriginalParams.length > 0) {
+						const error = compareContent(inputContent, outputContent)
+						if (error) {
+							Console.log(error)
+							return error
+						}
+
 					} else {
 						Console.log(outputContent)
 					}

edge/compareContent.js

@@ -0,0 +1,43 @@
+const _ = require('lodash')
+
+const createComparableLines = text => text
+	.replace(/\r/g, '¶')
+	.replace(/\t/g, '→')
+	.replace(/^\s+/gm, spaces => _.repeat('·', spaces.length))
+	.split('\n')
+
+function compareContent(actualContent, expectContent) {
+	if (actualContent === expectContent) {
+		return
+	}
+
+	const resultLines = createComparableLines(actualContent)
+	const expectLines = createComparableLines(expectContent)
+
+	let lineIndex = -1
+	while (++lineIndex < Math.min(resultLines.length, expectLines.length)) {
+		if (resultLines[lineIndex] !== expectLines[lineIndex]) {
+			let markers = ''
+			let charIndex = -1
+			const charLimit = Math.max(resultLines[lineIndex].length, expectLines[lineIndex].length)
+			while (++charIndex < charLimit) {
+				if (resultLines[lineIndex][charIndex] !== expectLines[lineIndex][charIndex]) {
+					markers += '^'
+				} else {
+					markers += ' '
+				}
+			}
+
+			return [
+				'The first mismatched was at line ' + (lineIndex + 1) + '.',
+				'  Actual: ' + resultLines[lineIndex],
+				'  Expect: ' + expectLines[lineIndex],
+				'          ' + markers
+			].join('\n')
+		}
+	}
+
+	return 'It was not clear to show the difference.'
+}
+
+module.exports = compareContent

spec/commandLineProcessor.js

@@ -49,7 +49,7 @@ describe('commandLineProcessor', () => {
 		})
 	})
 
-	it('prints the formatted content given no formatting options', () => {
+	it('prints the formatted content, given no formatting options', () => {
 		const inputContent = createCodeForFormatting(`
 		body
 		  display none
@@ -69,7 +69,7 @@ describe('commandLineProcessor', () => {
 	})
 
 	;['--options', '-p'].forEach(param => {
-		it('prints the formatted content given the formatting options in JSON', () => {
+		it('prints the formatted content, given the formatting options in JSON', () => {
 			const inputContent = createCodeForFormatting(`
 			body
 			  display none
@@ -96,7 +96,7 @@ describe('commandLineProcessor', () => {
 	})
 
 	;['--options', '-p'].forEach(param => {
-		it('prints the formatted content given the formatting options in YAML', () => {
+		it('prints the formatted content, given the formatting options in YAML', () => {
 			const inputContent = createCodeForFormatting(`
 			body
 			  display none
@@ -162,6 +162,39 @@ describe('commandLineProcessor', () => {
 		})
 	})
 
+	;['--compare', '-c'].forEach(param => {
+		it('prints no errors, given a well-formatted content', () => {
+			const inputContent = createCodeForFormatting(`
+			body {
+				display: none;
+			}
+			`)
+
+			fs.writeFileSync(inputTempFile, inputContent)
+			const errors = process('format', [inputTempFile, param], Console)
+
+			expect(errors.length).toBe(0)
+		})
+
+		it('prints the difference between the input and the formatted content', () => {
+			const inputContent = createCodeForFormatting(`
+			body {
+				display none
+			}
+			`)
+
+			fs.writeFileSync(inputTempFile, inputContent)
+			const errors = process('format', [inputTempFile, param], Console)
+
+			expect(errors[0]).toEqual([
+				'The first mismatched was at line 2.',
+				'  Actual: →display none',
+				'  Expect: →display: none;',
+				'                  ^^^^^^^',
+			].join('\n'))
+		})
+	})
+
 	it('throws an error given an unknown command', () => {
 		expect(() => { process('unknown', [], Console) }).toThrow()
 	})

test/runner.js

@@ -18,47 +18,11 @@ const pt = require('path')
 const _ = require('lodash')
 const Stylus = require('stylus')
 const format = require('../edge/format')
+const compareContent = require('../edge/compareContent')
 
 const filesAndDirectories = _.chain(ps.argv.length > 2 ? ps.argv.slice(2) : ['*']).map(para => glob.sync('spec/' + para)).flatten().value()
 const filesOnly = path => pt.extname(path) === '.js'
 const directoriesOnly = path => pt.extname(path) === ''
-const createComparableLines = text => text.replace(/\r/g, '¶').replace(/\t/g, '→').replace(/^\s+/gm, spaces => _.repeat('·', spaces.length)).split('\n')
-const createComparisonTest = (actualContent, expectContent, stack) => {
-	const resultLines = createComparableLines(actualContent)
-	const expectLines = createComparableLines(expectContent)
-
-	let lineIndex = -1
-	const lineLimit = Math.min(resultLines.length, expectLines.length)
-	while (++lineIndex < Math.min(resultLines.length, expectLines.length)) {
-		if (resultLines[lineIndex] !== expectLines[lineIndex]) {
-			let diffs = ''
-			let charIndex = -1
-			const charLimit = Math.max(resultLines[lineIndex].length, expectLines[lineIndex].length)
-			while (++charIndex < charLimit) {
-				if (resultLines[lineIndex][charIndex] !== expectLines[lineIndex][charIndex]) {
-					diffs += '^'
-				} else {
-					diffs += ' '
-				}
-			}
-
-			return fail({
-				message: [
-					'The first mismatched was at line ' + (lineIndex + 1) + '.',
-					'  Actual: ' + resultLines[lineIndex],
-					'  Expect: ' + expectLines[lineIndex],
-					'          ' + diffs
-				].join('\n'),
-				stack
-			})
-		}
-	}
-
-	return fail({
-		message: 'It was not clear to show the difference. Please check out the files below.',
-		stack
-	})
-}
 
 filesAndDirectories.filter(directoriesOnly).forEach(directory => {
 	const optionFilePath = pt.join(directory, 'formattingOptions.json')
@@ -91,10 +55,8 @@ filesAndDirectories.filter(directoriesOnly).forEach(directory => {
 
 			const actualContent = format(inputContent, formattingOptions)
 
-			if (actualContent === outputContent) {
-				expect(true).toBeTruthy()
-
-			} else {
+			const errorMessage = compareContent(actualContent, outputContent)
+			if (errorMessage) {
 				fs.writeFileSync(inputFormattedFilePath, actualContent)
 
 				const stack = [
@@ -104,7 +66,12 @@ filesAndDirectories.filter(directoriesOnly).forEach(directory => {
 					outputFilePath,
 				].map(path => pt.resolve(path)).join('\n')
 
-				createComparisonTest(actualContent, outputContent, stack)
+				fail({
+					message: errorMessage,
+					stack,
+				})
+			} else {
+				expect(true).toBeTruthy()
 			}
 		})
 
@@ -131,19 +98,22 @@ filesAndDirectories.filter(directoriesOnly).forEach(directory => {
 				// Do nothing
 			}
 
-			if (actualContent === outputContent) {
-				expect(true).toBeTruthy()
-
-			} else {
+			const errorMessage = compareContent(actualContent, outputContent)
+			if (errorMessage) {
 				fs.writeFileSync(outputFormattedFilePath, actualContent)
 
-				stack = [
+				const stack = [
 					outputFilePath,
 					outputFormattedFilePath,
 					outputDebuggingFilePath,
 				].map(path => pt.resolve(path)).join('\n')
 
-				createComparisonTest(actualContent, outputContent, stack)
+				fail({
+					message: errorMessage,
+					stack,
+				})
+			} else {
+				expect(true).toBeTruthy()
 			}
 		})
 	})