test_that("get_layout_structure treats <aside> as sidebar for vertical layout", {
  # Build a minimal aside tag as a sidebar
  aside_tag <- shiny::tags$aside(
  class = "custom-aside navbar-vertical",
    shiny::tags$ul(class = "navbar-nav pt-lg-3", shiny::tags$li("item"))
  )

  # Use tabler_page to build the full page for vertical layout
  page <- tabler_page(title = "Test", navbar = aside_tag, body = tabler_body("hi"), layout = "vertical")

  # Convert to HTML string for assertions
  html_str <- as.character(page)

  # Expect the aside to appear and have the vertical sidebar class present
  expect_true(grepl("<aside", html_str))
  expect_true(grepl("navbar-vertical", html_str))
})