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.
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 –
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
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 🙂