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    • By Christian Butcher
      Hi,
      I'm writing unit tests for some logging code (OK... so I suppose testing the actual logging class would be integration testing, but...) and have (at present) two disk logging classes and an in-memory test implementation.
      My test suite/case arrangement is currently a bit of a mess (understatement) and what I really want to do is run the same set of tests using each logging implementation. Obviously I don't want to code up the same tests repeatedly (and have to maintain a set of multiples).
      The solution as I understand it is to store a class object of the type to test in either the Suite or the Case (or both?) and then always read from private data when running a test. Writing the individual tests in this way is fine. My confusion lies in the best way to arrange the Suites and Cases to do this.
      In particular, if I have some DiskLoggerTestCase containing a collection of tests (for simplicity, all of my tests) and with the Logger object as private data of the Case, then I can create a Suite with code like below in New.vi (duplicatedCasePerSuite.png). Here, I build an array of each Logging object, then use a Write accessor and an autoindexing For loop to build the Suite. Problem: In the VI Tester UI, I see "DiskLoggerTestSuite:DiskLoggerTestCase, DiskLoggerTestSuite:DiskLoggerTestCase". There appears to be no way to distinguish or add names separately (if this is incorrect, I'd love to know how to change it).
      My second attempt (SuitePerImplementation.png) was to create a new Suite for the single TestCase, with each suite having a new name but the same TestCase (and using the write accessor, without a For loop). This works out, but means I now need to create a new suite for each additional implementation. It's not so terrible, but changes have to be reproduced in each suite if I want to modify something. Further, if I have more than one TestCase, it isn't possible to place them in a loop without reorganising them to inherit from a shared class providing the "Write Logging Object" VI as Dynamic Dispatch. Adding cases that don't use this require a new loop to discover their test methods. Duplicate code again rears its head.
      My next attempt will be to create one Suite of TestCases, in which the Suite has a Logging object, and it passes the object to the necessary cases, whilst allowing me to then create a set of owning Suites that each contain the first Suite. This is probably more or less the same as the second approach, but should at least compartmentalise some of the changes needed when adding Test Cases and separate adding Test Cases (change to the first Suite) from adding implementations (add a new Suite of the second type).
       
      Does anyone know the way this should really be done? I feel l'm missing a good solution and just creating difficult-to-maintain messes.


    • By ShaunR
      Name: VIM HAL Demo
      Submitter: ShaunR
      Submitted: 25 Sep 2015
      Category: *Uncertified*
      LabVIEW Version: 2009License Type: MIT



      This is an experimental demo to investigate VIMs (vi macros). It was a bit of fun to see if VIMs could be used to encapsulate events in LabVIEW which was a bugbear of mine for quite some time. You can see the entire thread here. VIMs are a NI experimental technology similar to Xnodes but less mature.
       
      The purpose of this release is to clarify the previously unstated licence since other forum topics are building on the original demo so they need a permissive licence (MIT). This release serves as an unambiguous statement to that effect. There are a few differences from the original which I have decided to call version 0.1 but they are minor.
       
      Note:
      This may or may not work for you out of the box. If it doesn't then please do not post. The purpose is to clarify the licence for others to build upon; not to provide a working example. The VIM technology is itself  experimental and unsupported by NI so most issues you will encounter will be due to this and It is unlikely there will be another version posted here.

      Click here to download this file
    • By ShaunR
      This is an experimental demo to investigate VIMs (vi macros). It was a bit of fun to see if VIMs could be used to encapsulate events in LabVIEW which was a bugbear of mine for quite some time. You can see the entire thread here. VIMs are a NI experimental technology similar to Xnodes but less mature.
       
      The purpose of this release is to clarify the previously unstated licence since other forum topics are building on the original demo so they need a permissive licence (MIT). This release serves as an unambiguous statement to that effect. There are a few differences from the original which I have decided to call version 0.1 but they are minor.
       
      Note:
      This may or may not work for you out of the box. If it doesn't then please do not post. The purpose is to clarify the licence for others to build upon; not to provide a working example. The VIM technology is itself  experimental and unsupported by NI so most issues you will encounter will be due to this and It is unlikely there will be another version posted here.
    • By dmurray
      I have a fundamental question on HALs and abstract methods that I'd like clarified, please. In my HAL's up to this point I've been using a parent with abstract methods, implementing concrete methods in the concrete product(s) (see here for example), and using dynamic dispatch as appropriate to execute the concrete method. I think this is a standard technique and it works fine for me.
       
      Now I have another layer of abstraction I want to implement, but in this case the concrete products share a lot of functionality and often I can get away with just executing the same method for each product. Should I just go ahead and implement this logic in the parent method? If I do, that means I no longer have abstract methods in my parent (right?), so am I breaking some 'good-practice' rules in OOP design? 
       
      Or am I just getting bogged down in semantics? 
       
      [by the way, I have loads of little niggling questions like these which I may ask as I'm going along in my OOP learning - hope you don't mind.] 
    • By dmurray
      Hi all.. I've been playing around with various HAL implementations for a while now, and I have a question on implementing some simple "state" functionality in the HAL. I've attached one such example - It's just an abstraction layer for a range of I2C Adapter modules that I use (or intend to use in the future). So my parent class is an abstract I2cAdapter, with overridable (dynamic dispatch) methods and exposed private data, effectively forming my interface to upper layers. Then at run-time I will just instantiate one concrete 'product'. (By the way, when I say "Adapter", it's nothing to do with the GOF pattern). 
       

       
      Now I also want to add some simple "state" functionality, and I'm hoping to get some pointers on the best way to approach this. The states I can identify in the HAL are:   1. Adapter physically disconnected (i.e. plugged out from the PC/laptop/whatever). I want upper layer(s) to know that this has happened. 2. Adapter connected, and enabled (normal operation). 3. Adapter connected, but disabled. Effectively I want the adapter to be in a high-Z state as far as the bus is concerned. (Of course this should happen automatically for a 'true' I2C adapter when its not accessing the bus, but unfortunately I can't guarantee that with the devices I'm using.)      I've looked at the GOF State pattern, but I think it's too elaborate for this situation. Also, I'm not sure it really applies here anyway.   As I look at it, the Enabled/Disabled states can be done simply - just add one (or two) abstract method(s) in my parent class and let each concrete adapter implement the necessary functionality. But what's the best way to handle the Disconnected state? Should the concrete adapter implement some functionality and inform the upper layer if a disconnect has occurred? Or should the upper layer have some sort of a periodic check of connectivity?    Maybe I should also add that one of the learning 'glitches' I'm having with LVOOP is the topic of collaboration between objects, and this post ties in with that to a certain extent. So any help would be appreciated.  
       
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