src/org/junit/internal/builders/JUnit3Builder.java

/**
 * 
 */
package org.junit.internal.builders;

import org.junit.internal.runners.JUnit38ClassRunner;
import org.junit.runner.Runner;
import org.junit.runners.model.RunnerBuilder;

public class JUnit3Builder extends RunnerBuilder {
	@Override
	public Runner runnerForClass(Class<?> testClass) throws Throwable {
		if (isPre4Test(testClass))
			return new JUnit38ClassRunner(testClass);
		return null;
	}

	boolean isPre4Test(Class<?> testClass) {
		return junit.framework.TestCase.class.isAssignableFrom(testClass);
	}
}