Here is a collection of test programs I have used on various Raspberry Pi based sensor projects such as
my cottage monitor: https://thingspeak.com/channels/54967
and the New Horizon model done for stelephane

mcp3008_test.py This assumes a 3.3 V full scale vref and reads all the
channels on a default connected MCP3008 ADC every 5 seconds.  Its a
good quick hack to see if you can read the adc voltages.  it can
easily be modified for other uses.
  run with:::  sudo python mcp3008_test.py

motorTest.py This is part of the Stellaphane 2016 project and runs a
stepper moter.  The motor class alone is a great simple stepper setup.
  run with::: sudo python motorTest.py <N steps> <direction>
     example:  sudo python motorTest.py 100 approach
               sudo python motorTest.py 200 depart


servo2.py will run a servo back an forth my changin the PWM on pin 16.  easily changed
  run with:::  sudo python servo2.py


testall.py
  similar to mcp3008_tst.py reads all the ADC channels, but also reads DHT22 sensors on pins 4 and 17.  Also dose serial input and output on TTYAMA0, the internal uart.
    run with:::  sudo python testall.py

All these examples are free to use for educational purposes.