Create initial tests

Tests are run via a PlatformIO project

platformio.ini

@@ -0,0 +1,23 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:nodemcuv2]
+platform = espressif8266
+board = nodemcuv2
+framework = arduino
+
+[env]
+monitor_speed = 115200
+test_build_src = true
+test_framework = unity
+lib_deps =
+    robtillaart/CRC @ 1.0.2
+    nrf24/RF24 @ 1.4.8
+    rlogiacco/CircularBuffer @ 1.3.3