I work mostly with functional programming languages where the function is the basic unit of code, what you say is true but is also true for "abstract entities".

I work mostly with functional programming languages where the function is the basic unit of code, what you say is true but is also true for "abstract entities". Not all classes need robust error checking if you control how they are being called. > The basic unit of code is the procedure I think ultimately this is where we think differently. If you are okay testing a whole class in an OOP context and calling that a unit test, then a test that calls multiple procedures (because one of them creates the input for the main procedure I want to test, for example) can also be considered a unit test.