Archive for 2009/12/22

Never take words for granted

Since this summer, I’ve been chasing an illusive error source in one of our systems. It’s nothing crucial, but sometimes the error pops up and it’s really annoying. It bugs my tester spirit that I haven’t understood why this occurs.

When I first found the error, I was told that it was because of duplicates in a list. “We have duplicates of value X in table Y.” But I couldn’t understand this. Duplicates are common in this table and not all of the rows with the duplicates have the error. Instead, the error was sometimes somewhere else.

Just today I realized that we just used a word very differently. I interpreted the statement as that multiple rows had the same value in the column. For example:

Value  Text
1           A
1           B
2           C
3           D
4           D

I would say that there are duplicates in the column “Value”. But that was not was the business people meant by duplicates in this case. What they referred to was that multiple rows could refer to the same physical entity. That is, that Value 3 and 4 could refer to the same entity (Text D). So, the error was someone completely different in the system.

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