[SystemSafety] State of the art for "safe Linux"

[Paul Sherwood]

On 2024-08-07 12:11, Prof. Dr. Peter Bernard Ladkin wrote:
> On 2024-08-07 11:38 , Paul Sherwood wrote:
>> On 2024-08-07 10:28, Prof. Dr. Peter Bernard Ladkin wrote:
>>>>> [Dewi Daniels] If
>>>>> your tests haven't achieved statement coverage, then there's code 
>>>>> that
>>>>> you've never executed, not even once, during your testing.
>>>> 
>>>> I understand the argument, but this last sentence is flawed.
>>> 
>>> How is the last sentence "flawed"? It seems to me a clear statement 
>>> of the obvious (which I imagine is what Dewi intended).
>> 
>> Because we can **test**, without creating **tests**. We may have 
>> executed the code, but not created tests for it.
> 
> Let me rephrase. Dewi's statement above is a tautology.

I looked up that word, to check it still means what I learned in 
school...

"Needless repetition of the same sense in different words; redundancy.
An instance of such repetition.
An empty or vacuous statement composed of simpler statements in a 
fashion that makes it logically true whether the simpler statements are 
factually true or false; for example, the statement Either it will rain 
tomorrow or it will not rain tomorrow."

In any case it's still clear that the logic of the original statement is 
flawed, as I explained.

> I imagine he made it in order to remind us of the importance of 
> statement coverage in constructing tests of critical software.

I expect he did. I am making these statements to remind folks of the 
clear, obvious weaknesses in statement coverage as an approach.