test: Add HotModuleReplacement test suite

spec/hot.spec.js

@@ -0,0 +1,89 @@
+/*
+ * Integration tests for caching
+ */
+
+/* eslint-env jest */
+'use strict';
+
+const path = require('path');
+const fs = require('fs');
+const webpack = require('webpack');
+const rimraf = require('rimraf');
+const WebpackRecompilationSimulator = require('webpack-recompilation-simulator');
+const HtmlWebpackPlugin = require('../index.js');
+
+const OUTPUT_DIR = path.join(__dirname, '../dist/caching-spec');
+
+// The WebpackRecompilationSimulator uses a loader to redirect the file writes to a temp directory.
+// As this would disable the default loader behaviour by design it has to be run in force mode
+const DEFAULT_LOADER = require.resolve('../lib/loader.js') + '?force';
+const DEFAULT_TEMPLATE = DEFAULT_LOADER + '!' + require.resolve('../default_index.ejs');
+
+jest.setTimeout(30000);
+process.on('unhandledRejection', r => console.log(r));
+process.traceDeprecation = true;
+
+describe('HtmlWebpackPluginHMR', () => {
+  beforeEach(done => {
+    rimraf(OUTPUT_DIR, done);
+  });
+
+  it('should not cause errors for the main compilation if hot-reload is active', () => {
+    const config = {
+      mode: 'development',
+      entry: path.join(__dirname, 'fixtures/index.js'),
+      output: {
+        path: OUTPUT_DIR
+      },
+      plugins: [
+        new webpack.HotModuleReplacementPlugin(),
+        new HtmlWebpackPlugin({ template: DEFAULT_TEMPLATE })
+      ]
+    };
+    const compiler = new WebpackRecompilationSimulator(webpack(config));
+    const jsFileTempPath = compiler.addTestFile(path.join(__dirname, 'fixtures/index.js'));
+    fs.writeFileSync(jsFileTempPath, 'module.exports = function calc(a, b){ return a + b };');
+    return compiler.startWatching()
+      // Change the template file and compile again
+      .then(() => {
+        fs.writeFileSync(jsFileTempPath, 'module.exports = function calc(a, b){ return a - b };');
+        return compiler.waitForWatchRunComplete();
+      })
+      .then(stats => {
+        expect(stats.compilation.errors).toEqual([]);
+      })
+      .then(() => compiler.stopWatching());
+  });
+
+  it('should not cause missing hot-reloaded code of the main compilation', () => {
+    const config = {
+      mode: 'development',
+      entry: path.join(__dirname, 'fixtures/index.js'),
+      target: 'node',
+      output: {
+        path: OUTPUT_DIR
+      },
+      plugins: [
+        new webpack.HotModuleReplacementPlugin(),
+        new HtmlWebpackPlugin({ template: DEFAULT_TEMPLATE })
+      ]
+    };
+    const compiler = new WebpackRecompilationSimulator(webpack(config));
+    const jsFileTempPath = compiler.addTestFile(path.join(__dirname, 'fixtures/index.js'));
+    fs.writeFileSync(jsFileTempPath, 'global = 1; module.hot.accept();');
+    return compiler.startWatching()
+      // Change the template file and compile again
+      .then(() => {
+        fs.writeFileSync(jsFileTempPath, 'global = 2; module.hot.accept();');
+        return compiler.waitForWatchRunComplete();
+      })
+      .then(stats => {
+        const hotUpdateJsFileNames = Object.keys(stats.compilation.assets).filter((fileName) => /\.hot-update\.js$/.test(fileName));
+        expect(hotUpdateJsFileNames).not.toEqual([]);
+        expect(hotUpdateJsFileNames.length).toEqual(1);
+        const hotUpdateFileSource = stats.compilation.assets[hotUpdateJsFileNames[0]].source();
+        expect(hotUpdateFileSource).not.toEqual('');
+      })
+      .then(() => compiler.stopWatching());
+  });
+});