test/API: validate channel arg (#8245)

test/functional/api/ui_spec.lua

@@ -0,0 +1,39 @@
+local helpers = require('test.functional.helpers')(after_each)
+local Screen = require('test.functional.ui.screen')
+local clear = helpers.clear
+local eq = helpers.eq
+local eval = helpers.eval
+local request = helpers.request
+
+describe('nvim_ui_attach()', function()
+  before_each(function()
+    clear()
+  end)
+  it('handles very large width/height #2180', function()
+    local screen = Screen.new(999, 999)
+    screen:attach()
+    eq(999, eval('&lines'))
+    eq(999, eval('&columns'))
+  end)
+  it('invalid option returns error', function()
+    local screen = Screen.new()
+    local status, rv = pcall(function() screen:attach({foo={'foo'}}) end)
+    eq(false, status)
+    eq('No such UI option', rv:match("No such .*"))
+  end)
+  it('validates channel arg', function()
+    assert.has_error(function() request('nvim_ui_try_resize', 40, 10) end,
+                     'UI not attached to channel: 1')
+    assert.has_error(function() request('nvim_ui_set_option', 'rgb', true) end,
+                     'UI not attached to channel: 1')
+    assert.has_error(function() request('nvim_ui_detach') end,
+                     'UI not attached to channel: 1')
+
+    local screen = Screen.new()
+    screen:attach({rgb=false})
+    assert.has_error(function()
+      request('nvim_ui_attach', 40, 10, { rgb=false })
+    end,
+    'UI already attached to channel: 1')
+  end)
+end)