Unit testing with Ceedling

There is no good written code without good written unit testing. Ceedling is a fantastic framework to help you test your code even for you microcontroller when you don't have the hardware

Part 0: Setting up the tools

There several frameworks we can use out there to test our code but we going to choose Ceedling since it was created explicitly to cover embedded needs. besides is relatively easy to use well documented and supported,

Part I: Testing functions

It is really easy to create unit tests in general but it will take some practice to master this new concept, if functions has parameters and return values, then things are straight forward , like the first example. here are a few more examples

Part II: Testing more complex data

This time we are going to refer a global variables like the ones who has an external reference in our codes, like in this example variable subs, that later is use in function subtraction

Part III: Unit testing private things

Static function are those you want to use only for internal driver use, and therefore their prototypes will never be written in

Part IV: Unit Testing State Machines

State machines is like a lot for embedded software, and for sure can be tested in all of their forms, but lest begin with the most simple example. A state machine that with three states that only moves the next state on each one.

Part IX: Unit Testing Registers

Unit testing with hardware with mock functions is really neat it allows you to test your upper layers without the need to have a hardware, but what if we are actually develop a low level driver that interact directly with the microcontroller registers,

Part V: Code Coverage

The goal of your unit test should be to test your code at a 100%, but his does not mean writing ALL the possible test cases for every single function, that will be incredible demanding and not really worthy the effort.

Part VI: Integration Testing

Part VII: Testing with Mocks

Part VIII: Mocking the STM32 library

According to the previous code on dummy.c our testing file should be similar as the previous one, we must mock the stm32g0xx_hal_adc.h, and call all the corresponding mock version use by the code under test. In this particular case we use ExpectAndReturn