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Lesson 6 - Java testing - Unit tests of real applications III

In the previous lesson, Java testing - Unit tests of real applications II, we discussed source code testing a DAO class for storing entities in a database. Today's tutorial concludes examples of unit tests in Java. We're going to show how to test random data generators by analyzing the data distribution and the Levenshtein distance.

Testing random data generators

As a final example, we've chosen a random token generator test for you. Generators of some, most often random or unique values, often occur in our applications. But how to test something that always has different values?

When generating numbers numbers, the basic test is usually to check the range of the values and their frequency of occurrence. Only valid numbers should be generated and each with the same probability. If the values are used for cryptographic purposes, such as generating passwords, there are other special testing algorithms to validate them but that goes beyond this course.

When generating strings, we test properties of these values, whether they meet the requirements and are really random (pseudo-random).

In programming, when comparing strings, we're probably going to encounter the two most common distance types:


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In this lesson, we'll learn to cover a random token generator with unit tests in jUnit. We'll analyze the distribution and the Levenshtein distance.

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Article has been written for you by David Capka
The author is a programmer, who likes web technologies and being the lead/chief article writer at He shares his knowledge with the community and is always looking to improve. He believes that anyone can do what they set their mind to.
Unicorn university The author learned IT at the Unicorn University - a prestigious college providing education on IT and economics.
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