[fix, spec] InputText:addChars() unicode handling (#3729)

Also rename from `addChar` to `addChars` for clarity.

Fixes #3703.

frontend/ui/widget/inputtext.lua

@@ -81,7 +81,7 @@ if Device.isTouchDevice() then
         if x > 0 and y > 0 then
             self.charpos = self.text_widget:moveCursor(x, y)
             if Device:hasClipboard() and Device.input.hasClipboardText() then
-                self:addChar(Device.input.getClipboardText())
+                self:addChars(Device.input.getClipboardText())
             end
             UIManager:setDirty(self.parent, function()
                 return "ui", self.dimen
@@ -247,13 +247,13 @@ function InputText:getKeyboardDimen()
     return self.keyboard.dimen
 end
 
-function InputText:addChar(char)
+function InputText:addChars(char)
     if self.enter_callback and char == '\n' then
         UIManager:scheduleIn(0.3, function() self.enter_callback() end)
         return
     end
     table.insert(self.charlist, self.charpos, char)
-    self.charpos = self.charpos + string.len(char)
+    self.charpos = self.charpos + #util.splitToChars(char)
     self:initTextBox(table.concat(self.charlist), true)
 end
 

frontend/ui/widget/physicalkeyboard.lua

@@ -119,7 +119,7 @@ function PhysicalKeyboard:onKeyPress(ev)
         if self.key_transformer then
             key = self.key_transformer[key]
         end
-        self.inputbox:addChar(key)
+        self.inputbox:addChars(key)
     end
 end
 

frontend/ui/widget/virtualkeyboard.lua

@@ -307,7 +307,7 @@ end
 
 function VirtualKeyboard:addChar(key)
     logger.dbg("add char", key)
-    self.inputbox:addChar(key)
+    self.inputbox:addChars(key)
 end
 
 function VirtualKeyboard:delChar()

spec/unit/inputtext_spec.lua

@@ -0,0 +1,57 @@
+describe("InputText widget module", function()
+    local InputText
+    local equals
+    setup(function()
+        require("commonrequire")
+        InputText = require("ui/widget/inputtext")
+
+        -- thanks to https://stackoverflow.com/a/32660766/2470572
+        equals = function(o1, o2, ignore_mt)
+            if o1 == o2 then return true end
+            local o1Type = type(o1)
+            local o2Type = type(o2)
+            if o1Type ~= o2Type then return false end
+            if o1Type ~= 'table' then return false end
+
+            if not ignore_mt then
+                local mt1 = getmetatable(o1)
+                if mt1 and mt1.__eq then
+                    --compare using built in method
+                    return o1 == o2
+                end
+            end
+
+            local keySet = {}
+
+            for key1, value1 in pairs(o1) do
+                local value2 = o2[key1]
+                if value2 == nil or equals(value1, value2, ignore_mt) == false then
+                    return false
+                end
+                keySet[key1] = true
+            end
+
+            for key2, _ in pairs(o2) do
+                if not keySet[key2] then return false end
+            end
+            return true
+        end
+    end)
+
+    describe("addChars()", function()
+        it("should add regular text", function()
+            InputText:initTextBox("")
+            InputText:addChars("a")
+            assert.is_true( equals({"a"}, InputText.charlist) )
+            InputText:addChars("aa")
+            assert.is_true( equals({"a", "a", "a"}, InputText.charlist) )
+        end)
+        it("should add unicode text", function()
+            InputText:initTextBox("")
+            InputText:addChars("Л")
+            assert.is_true( equals({"Л"}, InputText.charlist) )
+            InputText:addChars("Луа")
+            assert.is_true( equals({"Л", "Л", "у", "а"}, InputText.charlist) )
+        end)
+    end)
+end)