Tycho build 7: Plug-in unit tests

During the previous tutorials we focused on building stuff from our productive code. But good development is test driven and requires a lot of unit testing. Tycho can integrate tests in the build process which automatically gives you test coverage on every build you do.

Tycho Tutorials

For a list of all tycho related tutorials see Tycho Tutorials Overview

Source code for this tutorial is available on github as a single zip archive, as a Team Project Set or you can browse the files online.

Step 1: Create a sample unit test

Unit tests for plug-ins should normally be provided as a fragment to the plug-in under test. Fragments allow to access all classes of the main plug-in without exporting them. If you use the same package name for your unit test class and the class under test you can even access package private methods.

Create a new Fragment Project named com.codeandme.tycho.plugin.test. Set the Host Plug-in ID to com.codeandme.tycho.plugin and adjust the version ranges accordingly.

Create a new JUnit Test Case named com.codeandme.tycho.plugin.ExampleViewTest.java with following content.

package com.example.tycho.plugin;

import static org.junit.Assert.*;

import org.junit.Test;

public class ExampleViewTest {

 @Test
 public void testID() {
  assertEquals("com.example.tycho.views.example", ExampleView.VIEW_ID);
 }
}

I admit, this is a very stupid test, but this tutorial is not about writing good unit tests, right?

Step 2: Add test fragment to tycho build

Once again convert your fragment project to a maven project. Set Packaging to eclipse-test-plugin and like before add the project to our master pom file.

That's it! Build your product and your tests will automatically run as part of your build process. Try changing the assertion to provoke an error.

The tycho surefire plugin works a bit differently compared to a JUnit Plug-in Test. Surefire will only load plugins that are referenced via dependencies by the test plugin. This means it will start the minimal set of bundles defined by the dependency tree. In contrary JUnit Plug-in Tests will load everything available in your workspace.

Check the documentation to see how to add additional dependencies.