Mike Harris' Testing and Quality Blog
Cause-effect diagrams are a useful technique that can be used to improve quality. Glenford J. Myers wrote that “a weakness of boundary value analysis and equivalence partitions is that they do not explore combinations of input circumstances”[1]. A technique that can be used to explore and describe combinations of inputs to an issue is a …
Continue reading “Using Ishikawa diagrams to improve quality”
How a company responds to a complaint about quality needs careful consideration. A model that we can use to explore this issue is Dr Deming’s Red Beads Experiment. We can extend the Red Beads Experiment to include a complaint from customers. I explored the Red Beads Experiment in a previous blog post The blog post …
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The Five Whys is a technique for finding the root cause of a problem. Toyota developed this technique and it is now widely used, including in software development. I was introduced to the Five Whys by Tom Gilb as part of a course he ran on Lean QA and have used the Five Whys in …
When we test we think about the users of the functionality and we include their needs in our testing. Creating categories of customers, such as internal and external, can help us understand our customers’ uses of the functionality. Dr Joseph Juran advocated viewing customers as either internal or external customers. Juran was born in Romania …
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Identifying what states exist in functionality and how changes in state take place enables testers to identify tests that should be executed. State transition diagrams provide simple notation for summarising states and how changes in states take place. I recently used a state transition diagram on a project and it helped me identify the tests …
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Recently I was testing the messages sent from an app to the user when I noticed that the messages were dependent on the interaction of three conditions. I used a decision table to analyse the messaging because decision tables show how many tests are required to test something that is affected by a group of …
Creating a tree diagram can be a helpful way to visualise functionality that is accessed via hierarchical structures like menus and the tree diagrams can help to plan testing. In my mind’s eye I often see functionality as a tree diagram. C.S French says that trees are “hierarchical data structures rather like the familiar family …
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I recently saw a comment about how testers should be able to use decision tables to aid their testing. I decided to refresh my understanding of them and these are the notes I created about them. Decision tables are an analytical tool. They are used to describe logic and can be helpful in understanding the …
Continue reading “Can decision tables help you test API endpoints?”
There is always more testing that can be done on a feature but there are reducing returns on testing a feature over time. At some point you need to stop testing, and the question as to when to stop is sometimes a difficult call. Also, sometimes there is more than one feature to be tested. …
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