Improving Unit Testing with SmartInspect

Introduction
Extending Unit Tests
Generating Log Reports
Conclusion

Introduction

This article uses the JUnit unit testing framework and the SmartInspect Java library to demonstrate the generating of log reports in unit tests. A slightly modified example of the original JUnit distribution is used to show the benefits of using SmartInspect in this way. Although this article and the related classes are specific to Java, the general concepts should also be adaptable to other unit testing frameworks.

For the purpose of this article I wrote a custom junit.framework.TestCase class which is called SmartInspectTestCase. This class handles the creation of the necessary log objects and automates the logging of the beginning, ending and occurred exceptions of tests. In order to make use of these features, test cases need to inherit from this class. The required JUnit extension classes used in this article and the following example can be downloaded here.

Extending Unit Tests

I demonstrate the generating of log reports with the well-known junit.samples.SimpleTest example included in the Junit distribution. The basic concept of JUnit is to have a set of tests bundled in a so called test case. A test case is represented by a class which inherits from junit.framework.TestCase and the tests are normal methods which begin with the prefix "test".

public class SimpleTest extends TestCase
{
    public void testAdd() {
        double result = 2 + 3;
        assertTrue("Addition failed", result == 6);
    }

    public void testDivisionByZero() {
        int zero = 0;
        int result = 8 / zero;
    }

    ...

    public static void main(String[] args) {
        junit.textui.TestRunner.run(SimpleTest.class);
    }
}

As you can see, it couldn't be much simpler. The junit.textui.TestRunner extracts all valid tests from the SimpleTest class and executes them accordingly. In order to use SmartInspect now to generate log reports of your unit tests you just need to apply the following simple modifications:

public class SimpleTest extends SmartInspectTestCase 
{
    public void testAdd() {
        double result = 2 + 3;
        assertTrue("Addition failed", result == 6);
    }

    public void testDivisionByZero() {
        int zero = 0;
        getSession().logWarning("Checking division by zero");
        int result = 8 / zero;
    }

    ...

    public static void main(String[] args) {
        junit.textui.TestRunner.run(SimpleTest.class);
    }
}

As you can see, the most important modification of the original example is the change of the super class. Instead of deriving directly from the junit.framework.TestCase class, this piece of code uses my SmartInspectTestCase class. This enables the tests to generate detailed log reports, which leads us to the next chapter.

Generating Log Reports

When executed, the example above generates a detailed log report. This report automatically contains the beginning, ending and occurred exceptions of every test. In addition to these information, you can also add log statements by yourself to improve the log even further (as shown in the testDivisionByZero method).

SmartInspect used for generating log reports in unit tests (larger image)

As you can see in the screenshot above, most properties of the log objects in the SmartInspectTestCase class will be adjusted to the current execution context. The name of the underlying session is automatically synchronized with the name of the current test, for example. Among other things, this leads to easy filtering in the SmartInspect Console. You can now, for instance, display the logging information of the tests independently from each other (as shown in the screenshot).

Conclusion

After reading this article you should now have an overview over how to improve unit tests with SmartInspect. Just by deriving from a different java.framework.TestCase class, normal JUnit unit tests are now able to generate detailed log reports. If you have any further questions about this topic do not hesitate to contact me at tg@gurock.com.

UnitTesting.zip (2 KB)

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