feat: add test cases for rang being realigned

tests/range-aligin.spec.tsx

@@ -0,0 +1,134 @@
+import { act, cleanup, render } from '@testing-library/react';
+import { spyElementPrototypes } from 'rc-util/lib/test/domHook';
+import React from 'react';
+import { DayRangePicker } from './util/commonUtil';
+
+describe('the popup arrow should be placed in the correct position.', () => {
+  let rangeRect = { x: 0, y: 0, width: 0, height: 0 };
+
+  beforeEach(() => {
+    rangeRect = {
+      x: 0,
+      y: 0,
+      width: 200,
+      height: 100,
+    };
+
+    document.documentElement.scrollLeft = 0;
+  });
+
+  beforeAll(() => {
+    jest.spyOn(document.documentElement, 'scrollWidth', 'get').mockReturnValue(1000);
+
+    // Viewport size
+    spyElementPrototypes(HTMLElement, {
+      clientWidth: {
+        get: () => 400,
+      },
+      clientHeight: {
+        get: () => 400,
+      },
+    });
+
+    // Popup size
+    spyElementPrototypes(HTMLDivElement, {
+      getBoundingClientRect() {
+        if (this.className.includes('rc-picker-dropdown')) {
+          return {
+            x: 0,
+            y: 0,
+            width: 300,
+            height: 100,
+          };
+        }
+        if (this.className.includes('rc-picker-range')) {
+          return rangeRect;
+        }
+      },
+      offsetWidth: {
+        get() {
+          if (this.className.includes('rc-picker-range-wrapper')) {
+            return rangeRect.width;
+          }
+          if (this.className.includes('rc-picker-range-arrow')) {
+            return 10;
+          }
+          if (this.className.includes('rc-picker-input')) {
+            return 100;
+          }
+          if (this.className.includes('rc-picker-dropdown')) {
+            return 300;
+          }
+        },
+      },
+      offsetLeft: {
+        get() {
+          if (this.className.includes('rc-picker-input')) {
+            return 0;
+          }
+        },
+      },
+    });
+    spyElementPrototypes(HTMLElement, {
+      offsetParent: {
+        get: () => document.body,
+      },
+    });
+  });
+
+  beforeEach(() => {
+    jest.useFakeTimers();
+  });
+
+  afterEach(() => {
+    cleanup();
+    jest.useRealTimers();
+  });
+
+  it('the arrow should be set to `inset-inline-start` when the popup is aligned to `bottomLeft`.', async () => {
+    render(<DayRangePicker open />);
+
+    await act(async () => {
+      jest.runAllTimers();
+
+      await Promise.resolve();
+    });
+    expect(document.querySelector('.rc-picker-range-arrow')).toHaveStyle({
+      'inset-inline-start': '0',
+    });
+  });
+
+  it('the arrow should be set to `inset-inline-end` when the popup is aligned to `bottomRight`.', async () => {
+    const mock = spyElementPrototypes(HTMLDivElement, {
+      getBoundingClientRect() {
+        if (this.className.includes('rc-picker-dropdown')) {
+          return {
+            x: 0,
+            y: 0,
+            width: 300,
+            height: 100,
+          };
+        }
+        if (this.className.includes('rc-picker-range')) {
+          return {
+            ...rangeRect,
+            x: 300,
+          };
+        }
+      },
+    });
+
+    render(<DayRangePicker open />);
+
+    await act(async () => {
+      jest.runAllTimers();
+
+      await Promise.resolve();
+    });
+    expect(document.querySelector('.rc-picker-range-arrow')).toHaveStyle({
+      'inset-inline-end': '0',
+    });
+
+    mock.mockRestore();
+  });
+});