Re: Blocks for scope control

Robert Klemme <>
Fri, 20 Jan 2012 08:41:01 +0100
On 20.01.2012 02:54, Arved Sandstrom wrote:

Another decent reason, in my opinion, is if the management of them is
not disciplined. An organization that doesn't even wonder whether they
are disciplined enough to manage assertions in code isn't, and others
that do ask the question may decide that they are not.

I think this does not necessarily need to be handled on organization
level. Why make it so big? Every developer can help himself and their
colleagues by using them in a reasonable way.

What I mean by this is, assertions are easy to put in. They are not
always correct when put in, and they have to be maintained in any case
as code changes (or at least removed if necessary). Existing obsolete
assertions need to be taken into account when adding new ones in the
same class or package, because if you enable one then you may enable
more. Or you remove old ones you don't understand, if you trust yourself
to understand the business rules from 4 years ago well enough to
classify the assertions as being defunct.

Assertions also have the effect that they force you to think about
certain - possibly not obvious - properties of the code / class at hand
when you change the code. So while an assertion may look tricky it
actually helps you when modifying code to not forget important aspects.
  This may be more tedious but it certainly helps code robustness in the
long run.

Let me put it this way: I would feel good about looking at code that had
assertions in it if I saw that they were also commented where necessary,
including traceability notes where that makes sense, *and* were
supported by unit tests that exercised the assertions.

I view assertions in part also as documentation. Often no additional
commenting is needed. I frequently have a private boolean method
"classInvariant" or with other (hopefully telling) name with checks and
has documentation of its own. In these cases you have the name of the
method plus documentation on the method.

Kind regards


remember.guy do |as, often| as.you_can - without end

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