test: add unit test for DevServerEntryPlugin (#2840)

Author: ylemkimon

test/server/utils/DevServerEntryPlugin.test.js

@@ -0,0 +1,72 @@
+'use strict';
+
+const isWebpack5 = require('../../helpers/isWebpack5');
+
+(isWebpack5 ? describe : describe.skip)('DevServerEntryPlugin', () => {
+  let plugin;
+  const options = {};
+  const entries = ['./foo.js', './bar.js'];
+
+  const createDependency = jest.fn();
+  const tapPromise = jest.fn();
+  const compiler = {
+    hooks: {
+      make: {
+        tapPromise,
+      },
+    },
+  };
+  const compilation = {
+    addEntry: jest.fn((_context, _dep, _options, cb) => cb()),
+  };
+
+  beforeEach(() => {
+    jest.setMock('webpack/lib/EntryPlugin.js', { createDependency });
+    const DevServerEntryPlugin = require('../../../lib/utils/DevServerEntryPlugin');
+    plugin = new DevServerEntryPlugin('context', entries, options);
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('should set property', () => {
+    expect(plugin.context).toBe('context');
+    expect(plugin.entries).toBe(entries);
+    expect(plugin.options).toBe(options);
+  });
+
+  it('should add hooks to add entries', async () => {
+    plugin.apply(compiler);
+    expect(tapPromise).toBeCalledTimes(1);
+    expect(tapPromise.mock.calls[0]).toMatchSnapshot();
+
+    await tapPromise.mock.calls[0][1](compilation);
+    expect(compilation.addEntry).toBeCalledTimes(entries.length);
+    expect(compilation.addEntry.mock.calls).toMatchSnapshot();
+
+    expect(createDependency).toBeCalledTimes(entries.length);
+    expect(createDependency.mock.calls).toMatchSnapshot();
+  });
+
+  it('should allow modifying entries after creation', async () => {
+    plugin.apply(compiler);
+    jest.clearAllMocks();
+
+    const newEntries = ['./foobar.js'];
+    plugin.entries = newEntries;
+    expect(plugin.entries).toBe(newEntries);
+
+    plugin.apply(compiler);
+
+    expect(tapPromise).toBeCalledTimes(1);
+    expect(tapPromise.mock.calls[0]).toMatchSnapshot();
+
+    await tapPromise.mock.calls[0][1](compilation);
+    expect(compilation.addEntry).toBeCalledTimes(newEntries.length);
+    expect(compilation.addEntry.mock.calls).toMatchSnapshot();
+
+    expect(createDependency).toBeCalledTimes(newEntries.length);
+    expect(createDependency.mock.calls).toMatchSnapshot();
+  });
+});

test/server/utils/__snapshots__/DevServerEntryPlugin.test.js.snap

@@ -0,0 +1,65 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`DevServerEntryPlugin should add hooks to add entries 1`] = `
+Array [
+  "DevServerEntryPlugin",
+  [Function],
+]
+`;
+
+exports[`DevServerEntryPlugin should add hooks to add entries 2`] = `
+Array [
+  Array [
+    "context",
+    undefined,
+    Object {},
+    [Function],
+  ],
+  Array [
+    "context",
+    undefined,
+    Object {},
+    [Function],
+  ],
+]
+`;
+
+exports[`DevServerEntryPlugin should add hooks to add entries 3`] = `
+Array [
+  Array [
+    "./foo.js",
+    Object {},
+  ],
+  Array [
+    "./bar.js",
+    Object {},
+  ],
+]
+`;
+
+exports[`DevServerEntryPlugin should allow modifying entries after creation 1`] = `
+Array [
+  "DevServerEntryPlugin",
+  [Function],
+]
+`;
+
+exports[`DevServerEntryPlugin should allow modifying entries after creation 2`] = `
+Array [
+  Array [
+    "context",
+    undefined,
+    Object {},
+    [Function],
+  ],
+]
+`;
+
+exports[`DevServerEntryPlugin should allow modifying entries after creation 3`] = `
+Array [
+  Array [
+    "./foobar.js",
+    Object {},
+  ],
+]
+`;