test: Add testing lib part of testcase

jest.config.js

@@ -1,4 +1,5 @@
 module.exports = {
   setupFiles: ['./tests/setup.js'],
   snapshotSerializers: [require.resolve('enzyme-to-json/serializer')],
+  setupFilesAfterEnv: ['<rootDir>/tests/setupFilesAfterEnv.ts']
 };

package.json

@@ -49,6 +49,8 @@
     "rc-util": "^5.19.2"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^5.16.4",
+    "@testing-library/react": "^12.0.0",
     "@types/classnames": "^2.2.9",
     "@types/enzyme": "^3.10.8",
     "@types/jest": "^26.0.23",

tests/github.spec.tsx

@@ -0,0 +1,107 @@
+import React from 'react';
+import { render, act } from '@testing-library/react';
+import { spyElementPrototypes } from 'rc-util/lib/test/domHook';
+import Overflow from '../src';
+
+import { _rs as onResize } from 'rc-resize-observer/lib/utils/observerUtil';
+
+interface ItemType {
+  label: React.ReactNode;
+  key: React.Key;
+}
+
+function renderItem(item: ItemType) {
+  return item.label;
+}
+
+function renderRest(items: ItemType[]) {
+  return `+${items.length}...`;
+}
+
+describe('Overflow.github', () => {
+  function getData(count: number) {
+    return new Array(count).fill(undefined).map((_, index) => ({
+      label: `Label ${index}`,
+      key: `k-${index}`,
+    }));
+  }
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    jest.useRealTimers();
+  });
+
+  const widths = {
+    'rc-overflow': 100,
+    'rc-overflow-item': 90,
+  };
+
+  const propDef = {
+    get() {
+      let targetWidth = 0;
+      Object.keys(widths).forEach(key => {
+        if (this.className.includes(key)) {
+          targetWidth = widths[key];
+        }
+      });
+
+      return targetWidth;
+    },
+  };
+
+  beforeAll(() => {
+    spyElementPrototypes(HTMLDivElement, {
+      clientWidth: propDef,
+      offsetWidth: propDef,
+    });
+  });
+
+  async function triggerResize(target: HTMLElement) {
+    await act(async () => {
+      onResize([{ target } as any]);
+      for (let i = 0; i < 10; i += 1) {
+        await Promise.resolve();
+      }
+    });
+  }
+
+  it('only one', async () => {
+    const { container } = render(
+      <Overflow<ItemType>
+        data={getData(2)}
+        itemKey="key"
+        renderItem={renderItem}
+        renderRest={renderRest}
+        maxCount="responsive"
+      />,
+    );
+
+    // width & rest resize
+    await triggerResize(container.querySelector('.rc-overflow'));
+    await triggerResize(container.querySelector('.rc-overflow-item-rest'));
+
+    act(() => {
+      jest.runAllTimers();
+    });
+
+    const items = Array.from(
+      container.querySelectorAll<HTMLDivElement>(
+        '.rc-overflow-item:not(.rc-overflow-item-rest)',
+      ),
+    );
+
+    for (let i = 0; i < items.length; i += 1) {
+      await triggerResize(items[i]);
+    }
+    act(() => {
+      jest.runAllTimers();
+    });
+
+    expect(container.querySelector('.rc-overflow-item-rest')).toHaveStyle({
+      opacity: 1,
+    });
+  });
+});

tests/setupFilesAfterEnv.ts

@@ -0,0 +1 @@
+import '@testing-library/jest-dom';