Adds check for setting rgb to rgbw in simpletest

Author: dunkmann00

examples/pypixelbuf_simpletest.py

@@ -12,8 +12,10 @@ def _transmit(self, buffer):  # pylint: disable=unused-argument
         self.called = True
 
 
-buf = TestBuf(20, "RGB", 1.0, auto_write=True)
+buf = TestBuf(20, "RGBW", 1.0, auto_write=True)
 buf[0] = (1, 2, 3)
+buf[1] = (1, 2, 3, 4)
+buf[2] = (2, 2, 2)
 
 print(buf[0])
 print(buf[0:2])