[Tutor] What exactly is "state"?

[Sydney Shall]

On 02/03/2015 18:03, Dave Angel wrote:
> On 03/02/2015 11:25 AM, Sydney Shall wrote:
>> I am a beginner and I am now at the strage of learning to write
>> unittests.
>> I have followed the current discussion entitled "How to test a class in
>> pyhton", and I am not clear precisely what is meant by state. In its
>> common meaning I can see some relevance. But is there a technical aspect
>> to the notion. I see it mentioned often and feel rather uncomfortable
>> that I know so little about it.
>> I have deliberately started a new thread.
>> Thanks.
>
> When I started composing this, there were no other replies.  Sorry for
> any duplication caused by that.
>
> Starting with a dictionary definition:
>
> http://www.merriam-webster.com/dictionary/state
> "the overall physical condition of something : the ability of something
> to be used, enjoyed, etc."
>
> Others:
>
>
> "The particular condition that someone or something is in at a specific
> time"
>
> "In computer science and automata theory, the state of a digital logic
> circuit or computer program is a technical term for all the stored
> information, at a given instant in time, to which the circuit or program
> has access."
>
> That last comes the closest to what I'd like to explain.
>
> For a given fragment of executing code, the state includes all local
> variables, all parameters, all closures, all visible globals (ie the
> ones that *could* be visible to the code.  It also includes indirectly
> the values of all environment variables, lots of system information like
> the current directory, the time, the network IP address.  It also
> includes the current phase of the moon, the astrological sign of the
> current president of France, and the number of specs of sand on the
> eastern shore of a certain Martian lake.
Thank you very much, Joel, Danny, Alan and Dave.
Your explanations are all very clear and very enlightening.
I shall have to change several of my unittests now. In good time.
I am particularly pleased with the examples; they clarify matters 
considerably for me.

Out of subject, I wonder from this exchange whether teaching should not 
always involve at least several teachers. Your replies are very 
complimentary!


-- 
Sydney