summaryrefslogtreecommitdiffstats
path: root/remote/test/puppeteer/test/src/golden-utils.ts
blob: 3ebe534aaee51238a5bf050029e42a89c7140cef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
/**
 * 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.
 */
import assert from 'assert';
import fs from 'fs';
import path from 'path';

import {diffLines} from 'diff';
import jpeg from 'jpeg-js';
import mime from 'mime';
import pixelmatch from 'pixelmatch';
import {PNG} from 'pngjs';

interface DiffFile {
  diff: string | Buffer;
  ext?: string;
}

const GoldenComparators = new Map<
  string,
  (
    actualBuffer: string | Buffer,
    expectedBuffer: string | Buffer,
    mimeType: string
  ) => DiffFile | undefined
>();

const addSuffix = (
  filePath: string,
  suffix: string,
  customExtension?: string
): string => {
  const dirname = path.dirname(filePath);
  const ext = path.extname(filePath);
  const name = path.basename(filePath, ext);
  return path.join(dirname, name + suffix + (customExtension || ext));
};

const compareImages = (
  actualBuffer: string | Buffer,
  expectedBuffer: string | Buffer,
  mimeType: string
): DiffFile | undefined => {
  assert(typeof actualBuffer !== 'string');
  assert(typeof expectedBuffer !== 'string');

  const actual =
    mimeType === 'image/png'
      ? PNG.sync.read(actualBuffer)
      : jpeg.decode(actualBuffer);

  const expected =
    mimeType === 'image/png'
      ? PNG.sync.read(expectedBuffer)
      : jpeg.decode(expectedBuffer);
  if (expected.width !== actual.width || expected.height !== actual.height) {
    throw new Error(
      `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}
  );
  return count > 0 ? {diff: PNG.sync.write(diff)} : undefined;
};

const compareText = (
  actual: string | Buffer,
  expectedBuffer: string | Buffer
): DiffFile | undefined => {
  assert(typeof actual === 'string');
  const expected = expectedBuffer.toString('utf-8');
  if (expected === actual) {
    return;
  }
  const result = diffLines(expected, actual);
  const html = result.reduce((text, change) => {
    text += change.added
      ? `<span class='ins'>${change.value}</span>`
      : change.removed
      ? `<span class='del'>${change.value}</span>`
      : change.value;
    return text;
  }, `<link rel="stylesheet" href="file://${path.join(__dirname, 'diffstyle.css')}">`);
  return {
    diff: html,
    ext: '.html',
  };
};

GoldenComparators.set('image/png', compareImages);
GoldenComparators.set('image/jpeg', compareImages);
GoldenComparators.set('text/plain', compareText);

export const compare = (
  goldenPath: string,
  outputPath: string,
  actual: string | Buffer,
  goldenName: string
): {pass: true} | {pass: false; message: string} => {
  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);
  assert(mimeType);
  const comparator = GoldenComparators.get(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) {
    const diffPath = addSuffix(actualPath, '-diff', result.ext);
    fs.writeFileSync(diffPath, result.diff);
  }

  return {
    pass: false,
    message: `${goldenName} mismatch! ${messageSuffix}`,
  };

  function ensureOutputDir() {
    if (!fs.existsSync(outputPath)) {
      fs.mkdirSync(outputPath);
    }
  }
};