JUnit 5 - How to write more test with less code

Introduction

In this article, I will show and explain how you can write more tests with relatively small changes in your code. Recently, one of my colleagues wrote a massive test with repetitive code. The difference between test cases was only data that was submitted to the service. I will use JUnit 5 in this article, but feel free to check the library docs you use for writing tests.

Problem

Let’s imagine the following situation: we have a service that accepts the following data and returns the following response.

{
  "operationType": "+",
  "operands": [
    1,
    2,
    3,
    4,
    5
  ]
} 

{
  "result": 15
}

Of course, we can write many tests to cover each aspect, but there is a better solution. Let me introduce to you TestFactory from JUnit 5. You may argue that artificial cases use a test factory, and I agree with you, but the article is designed to give you an idea of how you can achieve more tests without writing more code.

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