add ability to set prefs

Author: ianfixes

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `DisplayManager` class for managing Xvfb instance if needed
 - `ArduinoCmd` captures and caches preferences
 - `ArduinoCmd` reports on whether a board is installed
+- `ArduinoCmd` sets preferences
 
 ### Changed
 - `DisplayManger.with_display` doesn't `disable` if the display was enabled prior to starting the block

exe/ci_system_check.rb

@@ -19,5 +19,13 @@
   got_problem = true if v != result
 end
 
+urls = [
+  "https://adafruit.github.io/arduino-board-index/package_adafruit_index.json",
+  "http://arduino.esp8266.com/stable/package_esp8266com_index.json"
+]
+
+result = arduino_cmd.set_pref("boardsmanager.additional.urls", urls.join(","))
+got_problem = true unless result
+
 abort if got_problem
 exit(0)

lib/arduino_ci/arduino_cmd.rb

@@ -51,6 +51,16 @@ def prefs
       ret
     end
 
+    # set a preference key/value pair
+    # @param key [String] the preference key
+    # @param value [String] the preference value
+    # @return [bool] whether the command succeeded
+    def set_pref(key, value)
+      success = run_with_gui_guess(" about preferences", "--pref", "#{key}=#{value}", "--save-prefs")
+      @prefs_cache[key] = value if success
+      success
+    end
+
     # run the arduino command
     # @return [Hash] {:out => StringIO, :err => StringIO }
     def run(*args, **kwargs)

spec/arduino_cmd_spec.rb

@@ -27,4 +27,15 @@
       expect(arduino_cmd.board_installed? "eggs:milk:wheat").to be false
     end
   end
+
+  context "set_pref" do
+    arduino_cmd = ArduinoCI::ArduinoCmd.autolocate!
+    ArduinoCI::DisplayManager::instance.enable
+
+    it "Sets key to what it was before" do
+      upload_verify = arduino_cmd.prefs_cache["upload.verify"]
+      result = arduino_cmd.set_pref("upload.verify", upload_verify)
+      expect(result).to be true
+    end
+  end
 end