Today I was preparing a presentation about Software Code quality for a TechTalk on Thursday. I made a search on the Internet about Automatic Unit test generators and Data Generators. I will present some tools I have tried. Today, we will speak of Randoop.

The first tool’s name is Randoop. This tool is existing since 2007 and its purpose is to generate automatically unit tests 🙂 Directly from your class definition!

To use it you have two choices:

• You can use your software JAR or classpath directory.
• You can include it in your test compile path (on Gradle or maven) and creates a main or unit test.

To explain shortly the theory, thanks to the Java reflection it’s quite easy to produce automatic tests validating some contracts of your API.

Some examples: – toString() should never return null or throws an Exception – equals() and compareTo() methods have a long list of constraints – Reflexivity: o.equals(o) == true – Symmetry: o1.equals(o2) == o2.equals(o1) – Transitivity: o1.equals(o2) && o2.equals(o3) ⇒ o1.equals(o3) – Equals to null: o.equals(null) == false – It does not throw an exception

Therefore this tool is generating unit tests with JUnit(TestSuite) for the list of classes you provide.

I have done some tests and you can reach 50-60% of coverage quite easily.

The main drawbacks of the solution are: – The unit tests are drawing a snapshot (precise picture) of your code and its behavior however some tests are really non-sense and you don’t want to edit them. – They don’t replace handwritten tests since the tool is not understanding the different between a String parameter emailand fullName. He will mostly use dumb strings.

About the technology, it’s not production-ready: – I had troubles with the jar and its dependency plume. – The JAR is a fat jar and coming with dependencies that broke my software.

In conclusion, I will fork the software and try to fix the problems to make it more popular 🙂