Monday, 27 September 2010

Hybrid Testing

There has been a lot of talk within the testing community about the scripted v non-scripted approach to testing. I have read and heard from people aligned to each school of thought trying to debunk the other schools approach. This can be very confusing to those that work in the profession of software testing. There are arguments on either side with people on either side presenting their point of view. I thought I would blog about my experiences of using both approaches in my day to day testing job.

When I first started in testing I worked for many companies which had adopted the Prince 2 methodology of software development and loosely followed a V-model process. This meant that requirements and specifications were gathered before any development work started. Using these documents as a tester I would do some gap analysis from a testing perspective to see where requirements contradicted each other and design specifications did not meet requirements. These were very heavyweight documents and it was a laborious task that engaged me as a tester to a certain point. Using these documents I would start to create scripted tests and build up a repository of test suites. Once the software started to be developed and I could gain access to certain features my engagement as a tester increased. I would run through my scripted tests and find that a large amount of them would need altering since I had made the wrong assumptions or the requirements and specification did not meet what was delivered. As I ‘explored’ the software I found more and more test ideas which would become test cases. The amount of discussions I had with senior management on why the number of test cases was increasing is another story altogether. I would spend a large amount of time adding detailed steps to the test scripts and then when we had another drop of the software run them again as a regression pack. I tried to automate the tests which for some easy parts worked and for others did not. What I did not know at the time was I was carrying out exploratory testing without knowing I was doing so. Once I had the software it was the most engaging time as a tester, it was what made me feel like I had done a good job by the end of the day.

So let us jump forward to today: - we have TDD, agile and a multitude of different approaches to software development. It is all about being flexible and developing software the customer needs quickly and efficiently and being able to adapt quickly when customer needs change. As testers we get to see and explore the software a lot sooner.

A lot has changed from a tester perspective we are now engaged more in the whole process, we are expected to have some knowledge of coding, IMO not always necessary but a good tool to have. We get to see the software a lot sooner and able to exercise and explore the software and to engage our testing minds to what the software should, could or may do. However have things changed that radically?

What has made me think about writing this blog has been the debates that have been going on about scripted vs. non-scripted. I am currently working on a new project in which there are many dependencies on internal components and external 3rd parties all of which are working to different timescales. Some of the components can be simulated which others cannot due to time constraints and other technical problems. We have some pretty good requirement documents and some design specifications. What we do not have at the moment is fully working end to end software. So I am back creating scripted test cases to meet the requirements, finding discrepancies in the documents and asking questions. The difference is that now I do not fully step out my scripts I create pointers on how to test the feature, I note test ideas that could be interesting to look at when the software arrives, I make a note of any dependencies that the software would require before testing that feature. So I create a story about testing the feature rather than create a step by step set of instructions. It is more a testing checklist rather than a test script. So with this I am combining both scripted and the non-scripted approach. I am sure a lot of readers will read this and think that they are doing the same.

The people who talk about exploratory testing have never said to my recollection that there is no need for scripted tests. Some of the requirements I have are fixed they will not change; the results should be as stated; so those requirements I can script or automate if possible. It does not mean you are doing anything wrong nor does it mean that you are not following an exploratory approach. Exploratory testing is just that an approach, it is not a method, it is not a do this and nothing else. It is a tool to use to enable you to test and hopefully engage you in testing rather than just being a checking robot. If you still create detailed step by step scripts then there is nothing wrong in doing that, I still do when required.

Exploratory testing can be used without the software, you can look at available documents and explore them for test ideas and new creative ways to test what the documents are stating, you can question, you can analysis you can make suggestions and improvements, you can use your brain.


  1. John,

    Good post. I agree with where you're coming from.

    One point to add/clarify. You mentioned: "The people who talk about exploratory testing have never said to my recollection that there is no need for scripted tests." I would state that even more strongly. James Bach, Cem Kaner, Michael Bolton, Jon Bach, etc. all say scripted tests are useful and often necessary but that they are used far too often and mis-used when testers are instructed to "paint by numbers" / "follow the test script to the letter without engaging their brains."

    For additional thought-provoking points on the scripted vs. exploratory vs. "Wait, it's not binary, it's a spectrum" topic, I'd suggest two links below:
    - Justin

  2. Hi Justin

    Thank you for the links and comments.

    All I want to do is put across my experience of using exploratory testing and try and move away from the arguements and get towards the doing.