org.junit.rules
Class RuleChain

java.lang.Object
  org.junit.rules.RuleChain

All Implemented Interfaces:

TestRule

public class RuleChain
   

    extends 
    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()

   

emptyRuleChain

public static RuleChain emptyRuleChain()

Returns a RuleChain without a TestRule. This method may be the starting point of a RuleChain.

Returns:

a RuleChain without a TestRule.

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:

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.

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