[SOLVED] Globally setting a JUnit runner instead of @RunWith

Globally setting a JUnit runner instead of @RunWith

Without looking into JUnit source itself (my next step) is there an easy way to set the default Runner to be used with every test without having to set @RunWith on every test? We've got a huge pile of unit tests, and I want to be able to add some support across the board without having to change every file.

Ideally I'm hope for something like: -Djunit.runner="com.example.foo".

Solution

I don't think this is possible to define globally, but if writing you own main function is an option, you can do something similar through code. You can create a custom RunnerBuilder and pass it to a Suite together with your test classes.

Class<?>[] testClasses = { TestFoo.class, TestBar.class, ... };
RunnerBuilder runnerBuilder = new RunnerBuilder() {
    @Override
    public Runner runnerForClass(Class<?> testClass) throws Throwable {
        return new MyCustomRunner(testClass);
    }
};
new JUnitCore().run(new Suite(runnerBuilder, testClasses));

This won't integrate with UI test runners like the one in Eclipse, but for some automated testing scenarios it could be an option.