“Maven Surefire 插件”在测试您的构建时意味着什么？

Question

I am working on understanding Maven and I'm learning about building your Java app with it. So when I do a :

maven package

It does build my jar as expected but I see in the output console that Maven does build tests (it always say that the test a run and there are no failure). I researched on the web about that and learned that Maven use a plugin called Maven Surefire. But I can't understand what does that plugin do to my code, what does the tests "means" ? What does the tests do with my code and how it works behind the console ?

Answer 1

The Maven surefire plugin runs the tests you have written. These are usually in the src/test/java folder. If you have none, the plugin does nothing.

Answer 2

Is this only one question? :D

So. Different things are going on.

You create an application with Java. To test the single components / packages / classes that you create most people use JUnit or TestNg . You usually have dedicated test classes that verify your production code behaves as intended without you clicking through all the things on every change.

When you now use maven to run your build the pom.xml file defines a packaging - in your case "jar" since you create a jar file. The packaging defines what set of default plugins run in the defined maven phases . You probably recognize package here. Maven executes all phases up to package and the registered / configured plugins.

To execute those tests maven provides the surefire plugin which supports running JUnit or TestNg tests. If you follow the directory conventions your tests reside in src/test/java and the surefire includes naming convention maven will execute those tests in every build (as this is the best practice). If you also want to write integration tests then there is the failsafe plugin . That plugin is not enabled by default and runs in different maven phases.

So the tests just run your production code - in fact they just do what you implement in the tests. They don't alter it in any way.

The maven introduction documentation has step by step explanations: Maven in 5 Minutes and the Getting Started Guide .

Starting from scratch this is probably a lot. So don't rush this. The build setup and test setup are very important things to have.