test(preset): add test cases for watcher util

packages/preset-dumi/src/utils/watcher.test.ts

@@ -0,0 +1,65 @@
+import fs from 'fs';
+import path from 'path';
+import {
+  watchFileChange,
+  triggerFileChange,
+  getWatchersForFile,
+  closeWatchersForFile,
+  closeWatcher,
+  saveFileOnDepChange,
+} from './watcher';
+
+describe('util: watcher', () => {
+  const parentPath = path.join(__dirname, './fixtures/watcher/parent.js');
+  const childPath = path.join(__dirname, './fixtures/watcher/child.js');
+  const otherPath = path.join(__dirname, './fixtures/watcher/other.js');
+
+  beforeAll(() => {
+    process.env.TEST_WATCHER = 'true';
+  });
+
+  afterAll(() => {
+    delete process.env.TEST_WATCHER;
+  });
+
+  it('basic watch', done => {
+    const watcherItem = watchFileChange(parentPath, () => {
+      closeWatcher(watcherItem);
+      expect(getWatchersForFile(parentPath).length).toEqual(0);
+      done();
+    });
+
+    expect(getWatchersForFile(parentPath).length).toEqual(1);
+    setTimeout(() => {
+      triggerFileChange(parentPath);
+    }, 10);
+  });
+
+  it('save on change', done => {
+    const watcher = fs.watch(parentPath, () => {
+      closeWatchersForFile(parentPath);
+      expect(getWatchersForFile(parentPath).length).toEqual(0);
+      watcher.close();
+      done();
+    });
+
+    saveFileOnDepChange(parentPath, childPath);
+    expect(getWatchersForFile(parentPath).length).toEqual(1);
+    setTimeout(() => {
+      triggerFileChange(childPath);
+    }, 10);
+  });
+
+  it('clear related watcher', () => {
+    saveFileOnDepChange(parentPath, childPath);
+    saveFileOnDepChange(childPath, otherPath);
+    expect(getWatchersForFile(parentPath).length).toEqual(2);
+    expect(getWatchersForFile(parentPath).length).toEqual(2);
+    expect(getWatchersForFile(childPath).length).toEqual(2);
+    expect(getWatchersForFile(otherPath).length).toEqual(1);
+    closeWatchersForFile(parentPath);
+    expect(getWatchersForFile(parentPath).length).toEqual(0);
+    expect(getWatchersForFile(childPath).length).toEqual(0);
+    expect(getWatchersForFile(otherPath).length).toEqual(0);
+  });
+});