c# ean 13 reader FURTHER READING For in C#

Generate EAN 13 in C# FURTHER READING For

scaffolding, see Jon Bentley s essay A Small Matter of 5 Programming in 6 Programming Pearls, 2d. Ed. 7 (2000).

Another kind of scaffolding is a fake routine that calls the real routine being tested. This is called a driver or, sometimes, a test harness. It can

The line between testing tools and debugging tools is fuzzy. For details on debugging tools, see Section 23.5, Debugging Tools Obvious and Not-SoObvious.

Call the object with a fixed set of inputs Prompt for input interactively and call the object with it Take arguments from the command line (in operating systems that support it) and call the object Read arguments from a file and call the object Run through predefined sets of input data in multiple calls to the object

A final kind of scaffolding is the dummy file, a small version of the real thing that has the same types of components that a full-size file has. A small dummy file offers a couple of advantages. Since it s small, you can know its exact contents and can be reasonably sure that the file itself is error-free. And since you create it specifically for testing, you can design its contents so that any error in using it is conspicuous.

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Obviously, building scaffolding requires some work, but if an error is ever detected in a class, you can reuse the scaffolding. And numerous tools exist to streamline creation of mock objects and other scaffolding. If you use scaffolding, the class can also be tested without the risk of its being affected by interactions with other classes. Scaffolding is particularly useful when subtle algorithms are involved. It s easy to get stuck in a rut in which it takes several minutes to execute each test case because the code being exercised is embedded in other code. Scaffolding allows you to exercise the code directly. The few minutes that you spend building scaffolding to exercise the deeply buried code can save hours of debugging time. You can use any of the numerous test frameworks available to provide scaffolding for your programs (JUnit, CppUnit, and so on). If your environment isn t supported by one of the existing test frameworks, you can write a few routines in a class and include a main() scaffolding routine in the file to test the class, even though the routines being tested aren t intended to stand by themselves. The main() routine can read arguments from the command line and pass them to the routine being tested so that you can exercise the routine on its own before integrating it with the rest of the program. When you integrate the code, leave the routines and the scaffolding code that exercises them in the file and use preprocessor commands or comments to deactivate the scaffolding code. Since it s preprocessed out, it doesn t affect the executable code, and since it s at the bottom of the file, it s not in the way visually. No harm is done by leaving it in. It s there if you need it again, and it doesn t burn up the time it would take to remove and archive it.

7 details on regression testing,

Regression testing, or retesting, is a lot easier if you have automated tools to check the actual output against the expected output. One easy way to check printed output is to redirect the output to a file and use a file-comparison tool such as Diff to compare the new output against the expected output that was sent to a file previously. If the outputs aren t the same, you have detected a regression error.