chore: add VDatePicker vitest file(#20517)

packages/vuetify/src/components/VDatePicker/__tests__/VDatePicker.spec.browser.tsx

@@ -0,0 +1,56 @@
+// Components
+import { VDatePicker } from '..'
+
+// Utilities
+import { render, screen } from '@test'
+import { fireEvent, waitFor } from '@testing-library/vue'
+import { ref } from 'vue'
+
+describe('VDatePicker', () => {
+  const selectDay = async (dayIndex: number, buttonClass = '.v-date-picker-month__day-btn') => {
+    const days = screen.getAllByCSS(buttonClass)
+    const dayButton = days[dayIndex]
+    await fireEvent.click(dayButton)
+  }
+
+  const selectMonth = async (monthName: string) => {
+    const monthButton = screen.getByCSS('.v-date-picker-controls__month-btn')
+    await fireEvent.click(monthButton)
+    const month = screen.getByText(monthName, { exact: false })
+    await fireEvent.click(month)
+  }
+
+  it('selects a range of dates', async () => {
+    const model = ref<unknown[]>([])
+    render(() => (
+        <VDatePicker v-model={ model.value } multiple="range" />
+    ))
+
+    // Select two days in the same month (e.g., 10th and 20th)
+    await selectDay(10)
+    await selectDay(20)
+
+    await waitFor(() => {
+      expect(model.value).toHaveLength(11) // Expect a 11-day range to be selected
+    })
+  })
+
+  it('selects a range of dates across month boundary', async () => {
+    const model = ref<unknown[]>([])
+    render(() => (
+      <VDatePicker v-model={ model.value } multiple="range" />
+    ))
+
+    // Select day 7 in January
+    await selectMonth('Jan')
+    await selectDay(7)
+
+    // Switch to February and select day 7
+    await selectMonth('Feb')
+    await selectDay(7)
+
+    await waitFor(() => {
+      expect(model.value).toHaveLength(32) // Expect a 32-day range spanning across two months
+    })
+  })
+})