Fix selection in calendar

frontend/src/pages/Calendar.test.tsx

@@ -10,6 +10,9 @@ vi.mock('@/context', () => ({
 
 vi.mock('@/hooks', () => ({
   usePlannedDays: vi.fn(),
+  useShowWeekNumbers: vi.fn(() => [false]),
+  getLastLeaveType: vi.fn(() => 'vacation'),
+  setLastLeaveType: vi.fn(),
 }))
 
 vi.mock('@/components/layout/Layout', () => ({
@@ -143,4 +146,32 @@ describe('Calendar', () => {
 
     expect(screen.getByTestId('calendar')).toBeInTheDocument()
   })
+
+  it('highlights date range live while dragging, before pointerup', () => {
+    ;(useWorkspace as any).mockReturnValue(mockWorkspace)
+    ;(usePlannedDays as any).mockReturnValue(mockPlannedDays)
+
+    render(<Calendar />)
+
+    const calendarDays = screen.getAllByTestId('calendar-day')
+    const currentMonthDays = calendarDays.filter((el) => !el.classList.contains('calendar-day--disabled'))
+
+    expect(currentMonthDays.length).toBeGreaterThanOrEqual(2)
+
+    const startDay = currentMonthDays[0] as HTMLElement
+    const endDay = currentMonthDays[3] as HTMLElement
+
+    // Fire pointerdown on first day
+    fireEvent.pointerDown(startDay)
+
+    // Fire pointerenter on later day WITHOUT firing pointerup
+    fireEvent.pointerEnter(endDay)
+
+    // The range should now have the --selected class before pointerup fires
+    const selectedDaysInRange = Array.from(calendarDays).filter((el) =>
+      el.classList.contains('calendar-day--selected')
+    )
+
+    expect(selectedDaysInRange.length).toBeGreaterThan(0)
+  })
 })