Once I have established what the software is to do I can worry about how to test it. For each of the actions above we could write a little test specification. Perhaps this is overkill for a simple job like this, in that I will know when the LCD works because I will see characters appear when I make it work properly, but for a larger program the test specification will be very important.

As I have already mentioned, you should never work on the basis that your test routine will involve just turning the system on to see what happens....

If you are working for a customer you should write a test specification even when the job is very simple. Think of it as a way of making sure you get paid, in that once your system meets the spec. you can down tools and demand some money!

For the LCD I have decided on the following test sequence:

  1. Start up the LCD (clear the screen and make the cursor appear)

  2. Clear the screen.

  3. Print the message "Hello World" on the top line

  4. Position the cursor at the middle of line 2 and print an 'X' character.


an airplane spiraling
Testing has large consequences for everyone