Comments for Miško Hevery

Comment on Dependency-Injection and JavaScript closures by Some useful readings | Joshy's microblog

Some useful readings | Joshy's microblog — Thu, 19 Jan 2012 16:42:57 +0000

[...] http://misko.hevery.com/2010/05/29/dependency-injection-and-javascript-closures/ [...]

Comment on Flaw: Constructor does Real Work by Dave Abrahams

Dave Abrahams — Tue, 17 Jan 2012 16:24:56 +0000

“It violates the Single Responsibility Principle,” while true, doesn’t have any obvious connection to testability. Could you explain that?

Thanks

Comment on Flaw: Brittle Global State & Singletons by Dave Abrahams

Dave Abrahams — Tue, 17 Jan 2012 14:00:43 +0000

On “JVM global state” vs. “Application shared state,” I agree there is a distinction but AFAICT it is only a matter of degree. The more sharing in an application, the more likely it is that you’ll need to use one “sharer” to set up conditions for another “sharer” to be tested. Or, you might easily fail to test the real conditions of your application because of an interaction that’s hidden in that shared, mutable state.

Comment on Flaw: Class Does Too Much by Dave Abrahams

Dave Abrahams — Tue, 17 Jan 2012 13:51:27 +0000

This article fails to explain how, if I’ve avoided the other three flaws, this particular flaw makes anything hard to test. There are lots of good non-testing-related arguments for why classes shouldn’t “do too much,” but how, specifically does it impact testability?

Comment on Ask! by karolina

karolina — Tue, 17 Jan 2012 11:43:16 +0000

Hi Misko,
two year ago we discussed your TTD-course at the Fac. of Math and Physics..during the time the situation changed and our vice-dean for informatics dept. is very interested in starting a new discussion about this matter..so, is your offer still valid?
regards, karolina

Comment on Move over Java, I have fallen in love with JavaScript by gmadar

gmadar — Mon, 16 Jan 2012 10:57:02 +0000

like any other solution. it has it’s good part and it’s bad parts. But hey – I love JavaScript

Comment on Static Methods are Death to Testability by David Zentgraf

David Zentgraf — Thu, 05 Jan 2012 04:28:58 +0000

Static functions are only problematic if they have unseen dependencies (violate dependency injection principles) and are not idempotent (have state). It’s not even about being leaf methods, that’s just a recursive problem of my first sentence. Static methods are just functions. Functions are extremely easy to test if they’re idempotent. That’s the functional principle. Functions may call other functions as much as they like and it doesn’t change anything about their being idempotent, as long as the functions they call are also idempotent. You can have a long chain of function calls hanging off of your static method, if none of them have any state there’s no problem. That’s why Math.abs() is easy to test, because it adheres to these principles. In the background it may make a thousand calls to hundreds of different functions, you don’t need to care.

So your rant against static methods is really a straw man rant against non-idempotent global functions, hence global state. It has nothing to do with being static. Static functions are fine and useful in OOP.

Comment on Ask! by Wouter de Kort

Wouter de Kort — Tue, 03 Jan 2012 10:26:17 +0000

Hi Misko,

I would like to say that I’m learning a lot by reading your blogs and looking at the presentations

I’m only having a question about how to inject disposable items.
I’m a .NET developer and I use things like
public class Presenter // Follows MVP pattern
{
….
public void DoStuff()
{
// Use a WCF service that should be closed properly (in test it’s mocked so no WCF)
using(IMyService service = ServiceFactory.Instance.Create()) { }
}
}
If I would pass service as a parameter, then the calling code would have to dispose of the service but the calling code is a codebehind file of my ASPX so that shouldn’t know about services and things like that.

How would you handle this? Make the whole Presenter disposable and pass the service in the constructor (trough a factory) or… ?

Thanks!
Wouter

Comment on Dependency Injection Myth: Reference Passing by Are singletons pathalogical liars? | Davelog

Are singletons pathalogical liars? | Davelog — Sat, 31 Dec 2011 23:57:07 +0000

[...] The response is apparently answered in the post Dependency Injection Myth: Reference Passing [...]

Comment on Singletons are Pathological Liars by Are singletons pathalogical liars? | Davelog

Are singletons pathalogical liars? | Davelog — Sat, 31 Dec 2011 23:48:33 +0000

[...] Miško Hevery thinks so: Singletons are Pathological Liars. [...]