test/ui: doublewidth rendering. multibyte and cmdwin chars in folded lines (#8534)

test/functional/ui/multibyte_spec.lua

@@ -0,0 +1,122 @@
+local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
+local clear = helpers.clear
+local feed = helpers.feed
+local feed_command = helpers.feed_command
+local insert = helpers.insert
+local funcs = helpers.funcs
+
+describe("multibyte rendering", function()
+  local screen
+  before_each(function()
+    clear()
+    screen = Screen.new(60, 6)
+    screen:attach({rgb=true})
+    screen:set_default_attr_ids({
+      [1] = {bold = true, foreground = Screen.colors.Blue1},
+      [2] = {background = Screen.colors.WebGray},
+      [3] = {background = Screen.colors.LightMagenta},
+      [4] = {bold = true},
+    })
+  end)
+
+  after_each(function()
+    screen:detach()
+  end)
+
+  it("works with composed char at start of line", function()
+    insert([[
+      ̊
+      x]])
+    feed("gg")
+     -- verify the modifier infact is alone
+    feed_command("ascii")
+    screen:expect([[
+      ^ ̊                                                           |
+      x                                                           |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      < ̊> 778, Hex 030a, Octal 1412                               |
+    ]])
+
+    -- a char inserted before will spontaneously merge with it
+    feed("ia<esc>")
+    feed_command("ascii")
+    screen:expect([[
+      ^å                                                           |
+      x                                                           |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      <a>  97,  Hex 61,  Octal 141 < ̊> 778, Hex 030a, Octal 1412  |
+    ]])
+  end)
+
+  it('works with doublewidth char at end of line', function()
+    feed('58a <esc>a馬<esc>')
+    screen:expect([[
+                                                                ^馬|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+                                                                  |
+    ]])
+
+    feed('i <esc>')
+    screen:expect([[
+                                                                ^ {1:>}|
+      馬                                                          |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+                                                                  |
+    ]])
+
+    feed('l')
+    screen:expect([[
+                                                                 {1:>}|
+      ^馬                                                          |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+                                                                  |
+    ]])
+  end)
+
+  it('clears left half of double-width char when right half is overdrawn', function()
+    feed('o-馬<esc>ggiab ')
+    screen:expect([[
+      ab ^                                                         |
+      -馬                                                         |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {4:-- INSERT --}                                                |
+    ]])
+
+    -- check double-with char is temporarily hidden when overlapped
+    funcs.complete(4, {'xx', 'yy'})
+    screen:expect([[
+      ab xx^                                                       |
+      - {2: xx             }                                          |
+      {1:~ }{3: yy             }{1:                                          }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {4:-- INSERT --}                                                |
+    ]])
+
+    -- check it is properly restored
+    feed('z')
+    screen:expect([[
+      ab xxz^                                                      |
+      -馬                                                         |
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {1:~                                                           }|
+      {4:-- INSERT --}                                                |
+    ]])
+  end)
+end)
+