November 2002
Intermediate to advanced
240 pages
5h 9m
English
Content preview from Test Driven Development: By Example
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Chapter 3
Equality for All
If I have an integer and I add 1 to it, I don’t expect the original integer to change, I expect to use the new value. Objects usually don’t behave that way. If I have a contract and I add one to its coverage, then the contract’s coverage should change (yes, yes, subject to all sorts of interesting business rules which do not concern us here).
We can use objects as values, as we are using our Dollar now. The pattern for this is Value Object. One of the constraints on Value Objects is that the values of the instance variables of the object never change once they have been set in the constructor.
There is one huge advantage to using Value Objects: you don’t have to worry about aliasing problems. Say I have one check and ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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