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The Easiest and the Hardest Methods to Write Unit Test For

I was wondering to find out the easiest methods to write unit tests for. I came up with a few results as the following ones…

a. A method that takes no parameter, perform calculations on only local data and always returns a constant value is the easiest to test. But the question is, is this at all important to have such methods?

b. A method that takes some parameters, and limits its operations only on the supplied parameters and local variables and returns some value or throws exception is also very easy to write a test for.

Now, we want all our methods to be easily unit testable. But the reality is, we cannot always have the most convenient forms for unit testing with real life methods.

And things start to go wrong as we have deviations from the ideal. Some of the most commonly found deviations are -
1. void methods that optionally throws exception
2. void methods without exceptions
3. Methods without parameters.
4. Methods having multilevel nesting and complex flow.
5. Methods that depends on other methods or classes or modules.
6. Methods having dependency on static methods.
7. Methods with a risk of runtime exception.

I will be posting rescue scenarios with appropriate reasoning to get around to the discomforts of the above listed deviations from ideal unit testing perspectives.

Stay tuned to get more on this…:-)