Re: Need help designing some JUnit tests

From:
Tom Anderson <twic@urchin.earth.li>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 21 May 2010 21:17:37 +0100
Message-ID:
<alpine.DEB.1.10.1005212114520.16922@urchin.earth.li>
On Fri, 21 May 2010, Patricia Shanahan wrote:

Rhino wrote:

Am I right in assuming that it is reasonable to bypass the sequence
testing in the case of my sorted list of Locales, given that I am using
a TreeMap which already guarantees the order? I assume you are just
including these tests to cover situations where I am generating a
sorted list out of thin air (without the benefit of the TreeXXX
Collection classes) so that I can be confident my code worked
correctly?


I would test it.

Suppose at some future time a programmer changes the Map implementation
e.g. from TreeMap to HashMap. That might be done in an attempt to
improve performance, or because of a future decision to standardize on
HashMap unless there is a specific reason to use a different
implementation. The future programmer could be yourself after you have
had time to forget why you used TreeMap.


Perhaps the method should be defined to return a SortedMap. If the test
says:

SortedMap<String, Locale> locales = LocaleHelper.getLocales(); // can't remember the actual name, sorry

Any attempt to return a non-Sorted Map, including redefining the method to
return a plain Map will be stopped in its tracks by the compiler.

Of course, it doesn't stop someone returning a TreeMap with a custom
comparator that does something bananas. Java's type system has its limits.

tom

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