infra: add snapshot tests

.eslintignore

@@ -1,3 +1,4 @@
 node_modules
 build
 tests
+integration-output

.github/workflows/tests.yaml

@@ -0,0 +1,34 @@
+name: Tests
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: ['**']
+
+jobs:
+  test:
+    name: Node v${{ matrix.node-version }} on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        node-version: [18.x]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - run: sudo apt-get update
+      - run: sudo apt-get install ghostscript
+      - run: sudo apt-get install graphicsmagick
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v2
+        with:
+          node-version: ${{ matrix.node-version }}
+          os: ${{ matrix.os }}
+          cache: 'npm'
+      - name: Install packages for project
+        run: npm ci
+      - name: Run tests
+        run: |
+          npm run test

.gitignore

@@ -14,4 +14,7 @@ coverage
 .DS_Store
 
 # integration
-integration-output
+integration-output
+
+# tests
+__tests__/stubs

.npmrc

@@ -1,2 +1,2 @@
 registry=https://registry.npmjs.org
-PUPPETEER_SKIP_CHROMIUM_DOWNLOAD = true
+PUPPETEER_SKIP_CHROMIUM_DOWNLOAD = true

.prettierignore

@@ -5,6 +5,7 @@
 
 # Build
 build
+integration-output
 
 #node
 node_modules

README.md

@@ -24,4 +24,22 @@ Run the `@diplodoc/docs2pdf` command. This will create PDF files right next to t
 
 ```
 npx -- @diplodoc/docs2pdf@latest -i ./docs-output
+```
+
+## Development
+
+### Prerequisites
+
+* node >= 18.x
+* graphicsmagick
+* ghostscript
+
+#### Don't have graphicsmagick and ghostscript yet?
+
+Follow [this](https://github.com/yakovmeister/pdf2image/blob/HEAD/docs/gm-installation.md) guide to install the required dependencies.
+
+### Run test
+
+```
+npm run test
 ```

__tests__/index.test.ts

@@ -0,0 +1,55 @@
+import {dirname, join, resolve} from 'path';
+
+import {toMatchImageSnapshot} from 'jest-image-snapshot';
+import {fromPath} from 'pdf2pic';
+import puppeteer from 'puppeteer';
+import {Browser} from 'puppeteer-core';
+
+import {generatePdf} from '../src';
+
+expect.extend({toMatchImageSnapshot});
+
+describe('integration', () => {
+    let browser: Browser;
+
+    const pdfFile = resolve(__dirname, '../integration-output/en/single-page.pdf');
+    const options = {
+        density: 100,
+        format: 'png',
+        width: 794,
+        height: 1123,
+    };
+    const convertPdf2Pic = fromPath(pdfFile, options);
+    const numberOfPages = 7;
+
+    beforeAll(async () => {
+        // @ts-ignore
+        browser = await puppeteer.launch({headless: true});
+
+        await generatePdf({
+            singlePagePath: join(dirname(pdfFile), 'single-page.json'),
+            browser,
+        });
+    });
+
+    it('works', async () => {
+        for (let currentPage = 1; currentPage <= numberOfPages; currentPage++) {
+            const {buffer: expectedImage} = await convertPdf2Pic(currentPage, {
+                responseType: 'buffer',
+            });
+
+            expect(expectedImage).toMatchImageSnapshot({
+                failureThreshold: 0.1,
+                failureThresholdType: 'percent',
+            });
+        }
+    });
+
+    afterAll(async () => {
+        if (!browser) {
+            return;
+        }
+
+        await browser.close();
+    });
+});

jest.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+    preset: 'ts-jest',
+    testEnvironment: 'node',
+    testMatch: ['**/?(*.)+(test).[tj]s?(x)'],
+    testTimeout: 1000000,
+};