Rules for software testing

When writing test cases, due to the following rules:
1. Local variables are neither input nor output, because they are released directly after the program runs.
2. If the function returns a value, the returned parameter is the internal definition of the function local variables, then write the output in the format of [function name@@].
3. During software testing, all sub-functions within it must be piled, except for inline functions.
4. Not all macros are constants, some Similar to SFR, these are registers and store variables, so they can be regarded as input and output during software testing
. Let's test the following statement