RuleChainTest.java

package org.junit.tests.experimental.rules;

import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.experimental.results.PrintableResult.testResult;
import static org.junit.rules.RuleChain.outerRule;

import java.util.ArrayList;
import java.util.List;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.RuleChain;
import org.junit.rules.TestWatcher;
import org.junit.runner.Description;

public class RuleChainTest {
    private static final List<String> LOG = new ArrayList<String>();

    private static class LoggingRule extends TestWatcher {
        private final String label;

        public LoggingRule(String label) {
            this.label = label;
        }

        @Override
        protected void starting(Description description) {
            LOG.add("starting " + label);
        }

        @Override
        protected void finished(Description description) {
            LOG.add("finished " + label);
        }
    }

    public static class UseRuleChain {
        @Rule
        public final RuleChain chain = outerRule(new LoggingRule("outer rule"))
                .around(new LoggingRule("middle rule")).around(
                        new LoggingRule("inner rule"));

        @Test
        public void example() {
            assertTrue(true);
        }
    }

    @Test
    public void executeRulesInCorrectOrder() throws Exception {
        testResult(UseRuleChain.class);
        List<String> expectedLog = asList("starting outer rule",
                "starting middle rule", "starting inner rule",
                "finished inner rule", "finished middle rule",
                "finished outer rule");
        assertEquals(expectedLog, LOG);
    }
}