Professional IronPython

Considering the Test Environment
 
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to a method and expects a certain output. However, IronPython can’t see into the method to test 
individual elements within it.
IronPython also can’t see private members of your application, so it can’t test absolutely every aspect 
of your application. If a private member is causing a problem, you need to use some other tools to 
find it. Of course, you can use IronPython to infer certain issues in private methods based on their 
effect on public methods, but this kind of logic can prove more troublesome than direct testing.
CoNSIdERINg THE TEST ENvIRoNmENT
Before you begin writing your test harness, you need to consider the test environment. The test environ-
ment determines how you test the application, be it a DLL or a desktop application with user access. 
The following list provides some criteria you need to consider as part of the test environment.
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Code access: You must define how the test harness will access the code. It’s important to 
determine whether the harness will test absolutely every method, property, event, and other 
application element individually, whether it will test elements in combination, or whether it 
will use a combination of individual and combined tests.
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Test ranges: A test harness must test both the possible and the impossible. For example, you 
might design a method to accept positive numbers from 0 through 5. However, the test harness 
must also test numbers greater than 5 and less than 0. In addition, it must test unexpected input, 
such as a string.
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User emulation: When working with some applications, you must determine how to emulate 
user activity. For example, you might write down a series of steps that the user will take to 
perform a certain activity and then execute those steps in your test harness. Of course, users 
are unpredictable; your script must also perform some haphazard and unpredictable steps 
and provide unexpected input. If you find that users are doing something you never expected, 
you must add it to the test harness.
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