Package org.junit.rules

Class RuleChain

  • All Implemented Interfaces:
    TestRule
    public class RuleChain
extends java.lang.Object
implements TestRule
    The RuleChain can be used for creating composite rules. You create a RuleChain with outerRule(TestRule) and subsequent calls of around(TestRule): 
     public abstract class CompositeRules {
   public static TestRule extendedLogging() {
     return RuleChain.outerRule(new LoggingRule("outer rule"))
                     .around(new LoggingRule("middle rule"))
                     .around(new LoggingRule("inner rule"));
   }
 }
 
     public class UseRuleChain {
   @Rule
   public final TestRule extendedLogging = CompositeRules.extendedLogging();

   @Test
   public void example() {
     assertTrue(true);
   }
 }
    writes the log 
     starting outer rule
 starting middle rule
 starting inner rule
 finished inner rule
 finished middle rule
 finished outer rule
    In older versions of JUnit (before 4.13) RuleChain was used for ordering rules. We recommend to not use it for this purpose anymore. You can use the attribute order of the annotation Rule or ClassRule for ordering rules.
    Since:
    4.10
    See Also:
    Rule.order(), ClassRule.order()

    • Method Detail

      • outerRule

        public static RuleChain outerRule​(TestRule outerRule)
        Returns a RuleChain with a single TestRule. This method is the usual starting point of a RuleChain.
        Parameters:
        outerRule - the outer rule of the RuleChain.
        Returns:
        a RuleChain with a single TestRule.

      • around

        public RuleChain around​(TestRule enclosedRule)
        Create a new RuleChain, which encloses the given TestRule with the rules of the current RuleChain.
        Parameters:
        enclosedRule - the rule to enclose; must not be null.
        Returns:
        a new RuleChain.
        Throws:
        java.lang.NullPointerException - if the argument enclosedRule is null

      • apply

        public Statement apply​(Statement base,
                       Description description)
        Modifies the method-running Statement to implement this test-running rule.
        Specified by:
        apply in interface TestRule
        Parameters:
        base - The Statement to be modified
        description - A Description of the test implemented in base
        Returns:
        a new statement, which may be the same as base, a wrapper around base, or a completely new Statement.