add mobile alert (#575)

* add mobile alert

* add comment

ios_tests/lib/ios/specs/ios/xcuitest_gestures.rb

@@ -8,6 +8,20 @@ def after_last
     screen.must_equal catalog
   end
 
+  def open_alert_ok_cancel
+    wait_true do
+      find_element(:name, 'Show OK-Cancel').click
+      find_element(:name, 'UIActionSheet <title>').displayed?
+    end
+  end
+
+  def open_alert_custom
+    wait_true do
+      find_element(:name, 'Show Customized').click
+      find_element(:name, 'UIActionSheet <title>').displayed?
+    end
+  end
+
   t 'before_first' do
     before_first
   end
@@ -58,8 +72,31 @@ def after_last
     find_element(:name, 'Serena Auroux').displayed?.must_equal true
   end
 
-  t 'after_last' do
+  t 'back to top' do
+    back_click
+  end
+
+  t 'alert' do
+    wait_true do
+      UI::Inventory.xcuitest? ? find_element(:name, 'Alerts').click : text('alerts').click
+      tag(UI::Inventory.navbar).name == 'Alerts' # wait for true
+    end
+
+    open_alert_ok_cancel
+    alert action: 'accept'
+
+    open_alert_ok_cancel
+    alert action: 'dismiss'
+
+    open_alert_custom
+    alert action: 'accept', button_label: 'Button1'
+  end
+
+  t 'back to top' do
     back_click
+  end
+
+  t 'after_last' do
     after_last
   end
 end

lib/appium_lib/ios/xcuitest_gestures.rb

@@ -142,6 +142,23 @@ def select_picker_wheel(element:, order:, offset: nil)
         args[:offset] = offset if offset
         execute_script 'mobile: selectPickerWheelValue', args
       end
+
+      # @param action [String] The following actions are supported: accept, dismiss and getButtons. Mandatory parameter
+      # @param button_label [String] The label text of an existing alert button to click on.
+      #   This is an optional parameter and is only valid in combination with accept and dismiss actions.
+      # @return nil or Selenium::WebDriver::Error::NoSuchAlertError if no action sheet or alert
+      #
+      #   ```ruby
+      #   alert action: "accept"
+      #   alert action: "dismiss"
+      #   ```
+      def alert(action:, button_label: nil)
+        return 'Set "accept", "dismiss" or "getButtons" for :action' unless %w(accept dismiss getButtons).include?(action)
+
+        args = { action: action }
+        args[:button_label] if button_label
+        execute_script 'mobile: alert', args
+      end
     end # module XcuitestGesture
   end # module Ios
 end # module Appium