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Partly related: Is equivalence partitioning [1] used much in the industry in software testing? [1] https://en.wikipedia.org/wiki/Equivalence_partitioning https

by vram22 10y ago

Partly related: Is equivalence partitioning [1] used much in the industry in software testing? [1] https://en.wikipedia.org/wiki/Equivalence_partitioning https://en.wikipedia.org/wiki/Equivalence_partitioning I came across the concept some years ago, IIRC, in the classic book The Art of Software Testing by Glenford Myers [2], and used it in a few projects. But have not really heard or read of it being used much, from people or on forums. [2] https://en.wikipedia.org/wiki/Glenford_Myers https://en.wikipedia.org/wiki/Glenford_Myers I think it can be complementary to some of the other approaches mentioned in this thread, which, BTW, is interesting.

mannykannot 10y ago
In the form discussed in [1], it gets pretty complicated when more than one operand is a variable, and they are derived from prior operations on the original data. Alternatively, identifying equivalence partitions from the semantics of the input data faces the problem that a faulty program may create invalid partitions, so some test cases for a given equivalence partition pass, while others fail.
- vram22 10y ago
  You raise some interesting points about issues with the method. I had used the approach in your second paragraph above. I agree that it can have the issue you mention. But is this not more or less the same as the issue that even test code can have bugs in it? But we still use test code. For that matter, even human testers doing manual testing can make mistakes. But we still do manual testing.
  - mannykannot 10y ago
    I agree that it is a valid technique, and in fact it is widely used: a minimal case is when we use a test account ID to stand for all accounts. The pessimist in me was looking for the exceptions, which is actually not a bad trait when you are testing.
    - vram22 10y ago
      > The pessimist in me was looking for the exceptions, which is actually not a bad trait when you are testing. Agreed :) Good discussion.

by vram22 10y ago

mannykannot 10y ago

In the form discussed in [1], it gets pretty complicated when more than one operand is a variable, and they are derived from prior operations on the original data. Alternatively, identifying equivalence partitions from the semantics of the input data faces the problem that a faulty program may create invalid partitions, so some test cases for a given equivalence partition pass, while others fail.

vram22 10y ago
You raise some interesting points about issues with the method. I had used the approach in your second paragraph above. I agree that it can have the issue you mention. But is this not more or less the same as the issue that even test code can have bugs in it? But we still use test code. For that matter, even human testers doing manual testing can make mistakes. But we still do manual testing.
- mannykannot 10y ago
  I agree that it is a valid technique, and in fact it is widely used: a minimal case is when we use a test account ID to stand for all accounts. The pessimist in me was looking for the exceptions, which is actually not a bad trait when you are testing.
  - vram22 10y ago
    > The pessimist in me was looking for the exceptions, which is actually not a bad trait when you are testing. Agreed :) Good discussion.