puppeteer/test/golden-utils.js

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/**
* Copyright 2017 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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const path = require('path');
const fs = require('fs');
const Diff = require('text-diff');
const mime = require('mime');
const PNG = require('pngjs').PNG;
const jpeg = require('jpeg-js');
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const pixelmatch = require('pixelmatch');
module.exports = {compare};
const GoldenComparators = {
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'image/png': compareImages,
'image/jpeg': compareImages,
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'text/plain': compareText
};
/**
* @param {?Object} actualBuffer
* @param {!Buffer} expectedBuffer
* @param {!string} mimeType
* @return {?{diff: (!Object:undefined), errorMessage: (string|undefined)}}
*/
function compareImages(actualBuffer, expectedBuffer, mimeType) {
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if (!actualBuffer || !(actualBuffer instanceof Buffer))
return { errorMessage: 'Actual result should be Buffer.' };
const actual = mimeType === 'image/png' ? PNG.sync.read(actualBuffer) : jpeg.decode(actualBuffer);
const expected = mimeType === 'image/png' ? PNG.sync.read(expectedBuffer) : jpeg.decode(expectedBuffer);
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if (expected.width !== actual.width || expected.height !== actual.height) {
return {
errorMessage: `Sizes differ: expected image ${expected.width}px X ${expected.height}px, but got ${actual.width}px X ${actual.height}px. `
};
}
const diff = new PNG({width: expected.width, height: expected.height});
const count = pixelmatch(expected.data, actual.data, diff.data, expected.width, expected.height, {threshold: 0.1});
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return count > 0 ? { diff: PNG.sync.write(diff) } : null;
}
/**
* @param {?Object} actual
* @param {!Buffer} expectedBuffer
* @return {?{diff: (!Object:undefined), errorMessage: (string|undefined)}}
*/
function compareText(actual, expectedBuffer) {
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if (typeof actual !== 'string')
return { errorMessage: 'Actual result should be string' };
const expected = expectedBuffer.toString('utf-8');
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if (expected === actual)
return null;
const diff = new Diff();
const result = diff.main(expected, actual);
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diff.cleanupSemantic(result);
let html = diff.prettyHtml(result);
const diffStylePath = path.join(__dirname, 'diffstyle.css');
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html = `<link rel="stylesheet" href="file://${diffStylePath}">` + html;
return {
diff: html,
diffExtension: '.html'
};
}
/**
* @param {?Object} actual
* @param {string} goldenName
* @return {!{pass: boolean, message: (undefined|string)}}
*/
function compare(goldenPath, outputPath, actual, goldenName) {
goldenPath = path.normalize(goldenPath);
outputPath = path.normalize(outputPath);
const expectedPath = path.join(goldenPath, goldenName);
const actualPath = path.join(outputPath, goldenName);
const messageSuffix = 'Output is saved in "' + path.basename(outputPath + '" directory');
if (!fs.existsSync(expectedPath)) {
ensureOutputDir();
fs.writeFileSync(actualPath, actual);
return {
pass: false,
message: goldenName + ' is missing in golden results. ' + messageSuffix
};
}
const expected = fs.readFileSync(expectedPath);
const mimeType = mime.getType(goldenName);
const comparator = GoldenComparators[mimeType];
if (!comparator) {
return {
pass: false,
message: 'Failed to find comparator with type ' + mimeType + ': ' + goldenName
};
}
const result = comparator(actual, expected, mimeType);
if (!result)
return { pass: true };
ensureOutputDir();
if (goldenPath === outputPath) {
fs.writeFileSync(addSuffix(actualPath, '-actual'), actual);
} else {
fs.writeFileSync(actualPath, actual);
// Copy expected to the output/ folder for convenience.
fs.writeFileSync(addSuffix(actualPath, '-expected'), expected);
}
if (result.diff) {
const diffPath = addSuffix(actualPath, '-diff', result.diffExtension);
fs.writeFileSync(diffPath, result.diff);
}
let message = goldenName + ' mismatch!';
if (result.errorMessage)
message += ' ' + result.errorMessage;
return {
pass: false,
message: message + ' ' + messageSuffix
};
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function ensureOutputDir() {
if (!fs.existsSync(outputPath))
fs.mkdirSync(outputPath);
}
}
/**
* @param {string} filePath
* @param {string} suffix
* @param {string=} customExtension
* @return {string}
*/
function addSuffix(filePath, suffix, customExtension) {
const dirname = path.dirname(filePath);
const ext = path.extname(filePath);
const name = path.basename(filePath, ext);
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return path.join(dirname, name + suffix + (customExtension || ext));
}