scrollbars fixed

.gitignore

@@ -1,5 +1,7 @@
 Cartographer.lua
 OverlayStats.lua
+lume.lua
+lurker.lua
 themes/metal/
 themes/space/
 .DS_STORE

modules/Element.lua

@@ -171,6 +171,7 @@ Public API methods to access internal state:
 ---@field objectPosition string? -- Image position like "center center", "top left", "50% 50%" (default: "center center")
 ---@field imageOpacity number? -- Image opacity 0-1 (default: 1, combines with element opacity)
 ---@field _loadedImage love.Image? -- Internal: cached loaded image
+---@field hideScrollbars boolean|{vertical:boolean, horizontal:boolean}? -- Hide scrollbars (boolean for both, or table for individual control)
 local Element = {}
 Element.__index = Element
 
@@ -1127,6 +1128,22 @@ function Element.new(props)
   self.scrollbarPadding = props.scrollbarPadding or 2
   self.scrollSpeed = props.scrollSpeed or 20
   
+  -- hideScrollbars can be boolean or table {vertical: boolean, horizontal: boolean}
+  if props.hideScrollbars ~= nil then
+    if type(props.hideScrollbars) == "boolean" then
+      self.hideScrollbars = { vertical = props.hideScrollbars, horizontal = props.hideScrollbars }
+    elseif type(props.hideScrollbars) == "table" then
+      self.hideScrollbars = {
+        vertical = props.hideScrollbars.vertical ~= nil and props.hideScrollbars.vertical or false,
+        horizontal = props.hideScrollbars.horizontal ~= nil and props.hideScrollbars.horizontal or false,
+      }
+    else
+      self.hideScrollbars = { vertical = false, horizontal = false }
+    end
+  else
+    self.hideScrollbars = { vertical = false, horizontal = false }
+  end
+
   -- Internal overflow state
   self._overflowX = false
   self._overflowY = false
@@ -1140,10 +1157,12 @@ function Element.new(props)
   self._maxScrollY = 0
 
   -- Scrollbar interaction state
-  self._scrollbarHovered = false
+  self._scrollbarHoveredVertical = false
+  self._scrollbarHoveredHorizontal = false
   self._scrollbarDragging = false
   self._hoveredScrollbar = nil -- "vertical" or "horizontal"
   self._scrollbarDragOffset = 0 -- Offset from thumb top when drag started
+  self._scrollbarPressHandled = false -- Track if scrollbar press was handled this frame
 
   return self
 end
@@ -1312,21 +1331,21 @@ function Element:_drawScrollbars(dims)
   local x, y = self.x, self.y
   local w, h = self.width, self.height
 
-  -- Determine thumb color based on state
+  -- Vertical scrollbar
+  if dims.vertical.visible and not self.hideScrollbars.vertical then
+    local trackX = x + w - self.scrollbarWidth - self.scrollbarPadding + self.padding.left
+    local trackY = y + self.scrollbarPadding + self.padding.top
+
+    -- Determine thumb color based on state (independent for vertical)
     local thumbColor = self.scrollbarColor
-  if self._scrollbarDragging then
+    if self._scrollbarDragging and self._hoveredScrollbar == "vertical" then
       -- Active state: brighter
       thumbColor = Color.new(math.min(1, thumbColor.r * 1.4), math.min(1, thumbColor.g * 1.4), math.min(1, thumbColor.b * 1.4), thumbColor.a)
-  elseif self._scrollbarHovered then
+    elseif self._scrollbarHoveredVertical then
       -- Hover state: slightly brighter
       thumbColor = Color.new(math.min(1, thumbColor.r * 1.2), math.min(1, thumbColor.g * 1.2), math.min(1, thumbColor.b * 1.2), thumbColor.a)
     end
 
-  -- Vertical scrollbar
-  if dims.vertical.visible then
-    local trackX = x + w - self.scrollbarWidth - self.scrollbarPadding + self.padding.left
-    local trackY = y + self.scrollbarPadding + self.padding.top
-
     -- Draw track
     love.graphics.setColor(self.scrollbarTrackColor:toRGBA())
     love.graphics.rectangle("fill", trackX, trackY, self.scrollbarWidth, dims.vertical.trackHeight, self.scrollbarRadius)
@@ -1337,10 +1356,20 @@ function Element:_drawScrollbars(dims)
   end
 
   -- Horizontal scrollbar
-  if dims.horizontal.visible then
+  if dims.horizontal.visible and not self.hideScrollbars.horizontal then
     local trackX = x + self.scrollbarPadding + self.padding.left
     local trackY = y + h - self.scrollbarWidth - self.scrollbarPadding + self.padding.top
 
+    -- Determine thumb color based on state (independent for horizontal)
+    local thumbColor = self.scrollbarColor
+    if self._scrollbarDragging and self._hoveredScrollbar == "horizontal" then
+      -- Active state: brighter
+      thumbColor = Color.new(math.min(1, thumbColor.r * 1.4), math.min(1, thumbColor.g * 1.4), math.min(1, thumbColor.b * 1.4), thumbColor.a)
+    elseif self._scrollbarHoveredHorizontal then
+      -- Hover state: slightly brighter
+      thumbColor = Color.new(math.min(1, thumbColor.r * 1.2), math.min(1, thumbColor.g * 1.2), math.min(1, thumbColor.b * 1.2), thumbColor.a)
+    end
+
     -- Draw track
     love.graphics.setColor(self.scrollbarTrackColor:toRGBA())
     love.graphics.rectangle("fill", trackX, trackY, dims.horizontal.trackWidth, self.scrollbarWidth, self.scrollbarRadius)
@@ -1370,8 +1399,8 @@ function Element:_getScrollbarAtPosition(mouseX, mouseY)
   local x, y = self.x, self.y
   local w, h = self.width, self.height
 
-  -- Check vertical scrollbar
+  -- Check vertical scrollbar (only if not hidden)
-  if dims.vertical.visible then
+  if dims.vertical.visible and not self.hideScrollbars.vertical then
     local trackX = x + w - self.scrollbarWidth - self.scrollbarPadding + self.padding.left
     local trackY = y + self.scrollbarPadding + self.padding.top
     local trackW = self.scrollbarWidth
@@ -1389,8 +1418,8 @@ function Element:_getScrollbarAtPosition(mouseX, mouseY)
     end
   end
 
-  -- Check horizontal scrollbar
+  -- Check horizontal scrollbar (only if not hidden)
-  if dims.horizontal.visible then
+  if dims.horizontal.visible and not self.hideScrollbars.horizontal then
     local trackX = x + self.scrollbarPadding + self.padding.left
     local trackY = y + h - self.scrollbarWidth - self.scrollbarPadding + self.padding.top
     local trackW = dims.horizontal.trackWidth
@@ -2699,17 +2728,31 @@ function Element:update(dt)
   -- Handle scrollbar hover detection
   local mx, my = love.mouse.getPosition()
   local scrollbar = self:_getScrollbarAtPosition(mx, my)
-  local wasHovered = self._scrollbarHovered
+  
-  if scrollbar then
+  -- Update independent hover states for vertical and horizontal scrollbars
-    self._scrollbarHovered = true
+  if scrollbar and scrollbar.component == "vertical" then
-    self._hoveredScrollbar = scrollbar.component
+    self._scrollbarHoveredVertical = true
+    self._hoveredScrollbar = "vertical"
   else
-    if not self._scrollbarDragging then
+    if not (self._scrollbarDragging and self._hoveredScrollbar == "vertical") then
-      self._scrollbarHovered = false
+      self._scrollbarHoveredVertical = false
-      self._hoveredScrollbar = nil
     end
   end
   
+  if scrollbar and scrollbar.component == "horizontal" then
+    self._scrollbarHoveredHorizontal = true
+    self._hoveredScrollbar = "horizontal"
+  else
+    if not (self._scrollbarDragging and self._hoveredScrollbar == "horizontal") then
+      self._scrollbarHoveredHorizontal = false
+    end
+  end
+  
+  -- Clear hoveredScrollbar if neither is hovered
+  if not scrollbar and not self._scrollbarDragging then
+    self._hoveredScrollbar = nil
+  end
+
   -- Handle scrollbar dragging
   if self._scrollbarDragging and love.mouse.isDown(1) then
     self:_handleScrollbarDrag(mx, my)
@@ -2718,6 +2761,25 @@ function Element:update(dt)
     self._scrollbarDragging = false
   end
 
+  -- Handle scrollbar click/press (independent of callback)
+  -- Check if we should handle scrollbar press for elements with overflow
+  local overflowX = self.overflowX or self.overflow
+  local overflowY = self.overflowY or self.overflow
+  local hasScrollableOverflow = (overflowX == "scroll" or overflowX == "auto" or overflowY == "scroll" or overflowY == "auto")
+  
+  if hasScrollableOverflow and not self._scrollbarDragging then
+    -- Check for scrollbar press on left mouse button
+    if love.mouse.isDown(1) and not self._scrollbarPressHandled then
+      local scrollbarPressed = self:_handleScrollbarPress(mx, my, 1)
+      if scrollbarPressed then
+        self._scrollbarPressHandled = true
+      end
+    elseif not love.mouse.isDown(1) then
+      -- Reset press handled flag when button is released
+      self._scrollbarPressHandled = false
+    end
+  end
+
   -- Handle click detection for element with enhanced event system
   if self.callback or self.themeComponent then
     -- Clickable area is the border box (x, y already includes padding)
@@ -2768,10 +2830,11 @@ function Element:update(dt)
           if love.mouse.isDown(button) then
             -- Button is pressed down
             if not self._pressed[button] then
-              -- Check if press is on scrollbar first
+              -- Check if press is on scrollbar first (skip if already handled)
-              if button == 1 and self:_handleScrollbarPress(mx, my, button) then
+              if button == 1 and not self._scrollbarPressHandled and self:_handleScrollbarPress(mx, my, button) then
                 -- Scrollbar consumed the event, mark as pressed to prevent callback
                 self._pressed[button] = true
+                self._scrollbarPressHandled = true
               else
                 -- Just pressed - fire press event and record drag start position
                 local modifiers = getModifiers()

testing/__tests__/30_scrollbar_features_tests.lua

@@ -0,0 +1,552 @@
+package.path = package.path .. ";./?.lua;./game/?.lua;./game/utils/?.lua;./game/components/?.lua;./game/systems/?.lua"
+
+local luaunit = require("testing.luaunit")
+require("testing.loveStub") -- Required to mock LOVE functions
+local FlexLove = require("FlexLove")
+local Gui, enums, Color = FlexLove.GUI, FlexLove.enums, FlexLove.Color
+
+local Positioning = enums.Positioning
+
+-- Create test cases for scrollbar features
+TestScrollbarFeatures = {}
+
+function TestScrollbarFeatures:setUp()
+  -- Clean up before each test
+  Gui.destroy()
+end
+
+function TestScrollbarFeatures:tearDown()
+  -- Clean up after each test
+  Gui.destroy()
+end
+
+-- ========================================
+-- Test 1: hideScrollbars with boolean value
+-- ========================================
+function TestScrollbarFeatures:testHideScrollbarsBooleanTrue()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    hideScrollbars = true,
+  })
+
+  -- Verify hideScrollbars is properly initialized
+  luaunit.assertNotNil(container.hideScrollbars)
+  luaunit.assertEquals(type(container.hideScrollbars), "table")
+  luaunit.assertEquals(container.hideScrollbars.vertical, true)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, true)
+end
+
+function TestScrollbarFeatures:testHideScrollbarsBooleanFalse()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    hideScrollbars = false,
+  })
+
+  -- Verify hideScrollbars defaults to showing scrollbars
+  luaunit.assertNotNil(container.hideScrollbars)
+  luaunit.assertEquals(container.hideScrollbars.vertical, false)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, false)
+end
+
+-- ========================================
+-- Test 2: hideScrollbars with table configuration
+-- ========================================
+function TestScrollbarFeatures:testHideScrollbarsTableVerticalOnly()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    hideScrollbars = { vertical = true, horizontal = false },
+  })
+
+  -- Verify only vertical scrollbar is hidden
+  luaunit.assertEquals(container.hideScrollbars.vertical, true)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, false)
+end
+
+function TestScrollbarFeatures:testHideScrollbarsTableHorizontalOnly()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    hideScrollbars = { vertical = false, horizontal = true },
+  })
+
+  -- Verify only horizontal scrollbar is hidden
+  luaunit.assertEquals(container.hideScrollbars.vertical, false)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, true)
+end
+
+function TestScrollbarFeatures:testHideScrollbarsTableBothHidden()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    hideScrollbars = { vertical = false, horizontal = false },
+  })
+
+  -- Verify both scrollbars are shown
+  luaunit.assertEquals(container.hideScrollbars.vertical, false)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, false)
+end
+
+-- ========================================
+-- Test 3: Default hideScrollbars behavior
+-- ========================================
+function TestScrollbarFeatures:testHideScrollbarsDefault()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+  })
+
+  -- Verify default is to show scrollbars (backward compatibility)
+  luaunit.assertNotNil(container.hideScrollbars)
+  luaunit.assertEquals(container.hideScrollbars.vertical, false)
+  luaunit.assertEquals(container.hideScrollbars.horizontal, false)
+end
+
+-- ========================================
+-- Test 4: Independent hover states initialization
+-- ========================================
+function TestScrollbarFeatures:testIndependentHoverStatesInitialization()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+  })
+
+  -- Verify independent hover states are initialized
+  luaunit.assertNotNil(container._scrollbarHoveredVertical)
+  luaunit.assertNotNil(container._scrollbarHoveredHorizontal)
+  luaunit.assertEquals(container._scrollbarHoveredVertical, false)
+  luaunit.assertEquals(container._scrollbarHoveredHorizontal, false)
+end
+
+-- ========================================
+-- Test 5: Scrollbar dimensions calculation
+-- ========================================
+function TestScrollbarFeatures:testScrollbarDimensionsCalculation()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Calculate scrollbar dimensions
+  local dims = container:_calculateScrollbarDimensions()
+
+  -- Verify dimensions structure
+  luaunit.assertNotNil(dims.vertical)
+  luaunit.assertNotNil(dims.horizontal)
+  luaunit.assertNotNil(dims.vertical.visible)
+  luaunit.assertNotNil(dims.horizontal.visible)
+end
+
+-- ========================================
+-- Test 6: Scroll position management
+-- ========================================
+function TestScrollbarFeatures:testScrollPositionSetAndGet()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow to set max scroll
+  container:_detectOverflow()
+
+  -- Set scroll position
+  container:setScrollPosition(50, 100)
+
+  -- Get scroll position
+  local scrollX, scrollY = container:getScrollPosition()
+  luaunit.assertEquals(scrollX, 50)
+  luaunit.assertEquals(scrollY, 100)
+end
+
+function TestScrollbarFeatures:testScrollPositionClamping()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow to set max scroll
+  container:_detectOverflow()
+
+  -- Try to set scroll position beyond max
+  container:setScrollPosition(1000, 1000)
+
+  -- Get scroll position - should be clamped to max
+  local scrollX, scrollY = container:getScrollPosition()
+  local maxScrollX, maxScrollY = container:getMaxScroll()
+  luaunit.assertEquals(scrollX, maxScrollX)
+  luaunit.assertEquals(scrollY, maxScrollY)
+end
+
+-- ========================================
+-- Test 7: Scroll by delta
+-- ========================================
+function TestScrollbarFeatures:testScrollByDelta()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Initial scroll position
+  container:setScrollPosition(50, 50)
+
+  -- Scroll by delta
+  container:scrollBy(10, 20)
+
+  -- Verify new position
+  local scrollX, scrollY = container:getScrollPosition()
+  luaunit.assertEquals(scrollX, 60)
+  luaunit.assertEquals(scrollY, 70)
+end
+
+-- ========================================
+-- Test 8: Scroll to top/bottom/left/right
+-- ========================================
+function TestScrollbarFeatures:testScrollToTop()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Set initial scroll position
+  container:setScrollPosition(50, 50)
+
+  -- Scroll to top
+  container:scrollToTop()
+
+  -- Verify position
+  local scrollX, scrollY = container:getScrollPosition()
+  luaunit.assertEquals(scrollY, 0)
+end
+
+function TestScrollbarFeatures:testScrollToBottom()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Scroll to bottom
+  container:scrollToBottom()
+
+  -- Verify position
+  local scrollX, scrollY = container:getScrollPosition()
+  local maxScrollX, maxScrollY = container:getMaxScroll()
+  luaunit.assertEquals(scrollY, maxScrollY)
+end
+
+function TestScrollbarFeatures:testScrollToLeft()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Set initial scroll position
+  container:setScrollPosition(50, 50)
+
+  -- Scroll to left
+  container:scrollToLeft()
+
+  -- Verify position
+  local scrollX, scrollY = container:getScrollPosition()
+  luaunit.assertEquals(scrollX, 0)
+end
+
+function TestScrollbarFeatures:testScrollToRight()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Scroll to right
+  container:scrollToRight()
+
+  -- Verify position
+  local scrollX, scrollY = container:getScrollPosition()
+  local maxScrollX, maxScrollY = container:getMaxScroll()
+  luaunit.assertEquals(scrollX, maxScrollX)
+end
+
+-- ========================================
+-- Test 9: Get scroll percentage
+-- ========================================
+function TestScrollbarFeatures:testGetScrollPercentage()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Scroll to middle
+  local maxScrollX, maxScrollY = container:getMaxScroll()
+  container:setScrollPosition(maxScrollX / 2, maxScrollY / 2)
+
+  -- Get scroll percentage
+  local percentX, percentY = container:getScrollPercentage()
+  luaunit.assertAlmostEquals(percentX, 0.5, 0.01)
+  luaunit.assertAlmostEquals(percentY, 0.5, 0.01)
+end
+
+-- ========================================
+-- Test 10: Has overflow detection
+-- ========================================
+function TestScrollbarFeatures:testHasOverflow()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows vertically
+  local child = Gui.new({
+    parent = container,
+    width = 150,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Check overflow
+  local hasOverflowX, hasOverflowY = container:hasOverflow()
+  luaunit.assertEquals(hasOverflowX, false)
+  luaunit.assertEquals(hasOverflowY, true)
+end
+
+-- ========================================
+-- Test 11: Get content size
+-- ========================================
+function TestScrollbarFeatures:testGetContentSize()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child with specific size
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 400,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Get content size
+  local contentWidth, contentHeight = container:getContentSize()
+  luaunit.assertEquals(contentWidth, 300)
+  luaunit.assertEquals(contentHeight, 400)
+end
+
+-- ========================================
+-- Test 12: Scrollbar configuration options
+-- ========================================
+function TestScrollbarFeatures:testScrollbarConfigurationOptions()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    scrollbarWidth = 20,
+    scrollbarRadius = 10,
+    scrollbarPadding = 5,
+    scrollSpeed = 30,
+    scrollbarColor = Color.new(1, 0, 0, 1),
+    scrollbarTrackColor = Color.new(0, 1, 0, 1),
+  })
+
+  -- Verify custom configuration
+  luaunit.assertEquals(container.scrollbarWidth, 20)
+  luaunit.assertEquals(container.scrollbarRadius, 10)
+  luaunit.assertEquals(container.scrollbarPadding, 5)
+  luaunit.assertEquals(container.scrollSpeed, 30)
+  luaunit.assertEquals(container.scrollbarColor.r, 1)
+  luaunit.assertEquals(container.scrollbarTrackColor.g, 1)
+end
+
+-- ========================================
+-- Test 13: Wheel scroll handling
+-- ========================================
+function TestScrollbarFeatures:testWheelScrollHandling()
+  local container = Gui.new({
+    x = 0,
+    y = 0,
+    width = 200,
+    height = 200,
+    overflow = "scroll",
+    positioning = Positioning.FLEX,
+  })
+
+  -- Add child that overflows
+  local child = Gui.new({
+    parent = container,
+    width = 300,
+    height = 300,
+  })
+
+  -- Detect overflow
+  container:_detectOverflow()
+
+  -- Set initial position away from top so we can scroll up
+  container:setScrollPosition(nil, 50)
+  local initialScrollX, initialScrollY = container:getScrollPosition()
+
+  -- Handle wheel scroll (vertical) - positive y means scroll up
+  local handled = container:_handleWheelScroll(0, 1)
+
+  -- Verify scroll was handled and position changed (scrolled up means lower scroll value)
+  luaunit.assertEquals(handled, true)
+  local scrollX, scrollY = container:getScrollPosition()
+  luaunit.assertTrue(scrollY < initialScrollY, "Expected scroll position to decrease when scrolling up")
+end
+
+-- Run the tests
+os.exit(luaunit.LuaUnit.run())