Add brightness testing code

Author: joerick

test_routine.tingapp/main.py

@@ -1,7 +1,7 @@
 import tingbot
 from tingbot import *
+import time
 
-# setup code here
 state = {
     'screen': 0,
 }
@@ -10,7 +10,7 @@
 def tick():
     state['screen'] += 1
 
-    if state['screen'] > 2:
+    if state['screen'] > 3:
         state['screen'] = 0
 
     if state['screen'] == 0:
@@ -22,6 +22,15 @@ def tick():
     elif state['screen'] == 2:
         screen.fill(color='grey')
         screen.text('Hello world!', color='white')
+    elif state['screen'] == 3:
+        screen.fill(color='white')
+        screen.text('Backlight!', color='black')
+        screen.update()
+        time.sleep(0.25)
+
+        for brightness in [75, 50, 25, 0, 25, 50, 75, 100]:
+            screen.brightness = brightness
+            time.sleep(0.25)
 
 @touch()
 def on_touch(xy):