xUnit Rule

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Rule とは？
JUnit 4 標準のルール
System Rules
Rule の適用順序を明示したい (RuleChain)
テストクラスで一度だけ実行される前処理・後処理 (@ClassRule)
Description からテストメソッドの情報を得る

Rule とは？ †

定型的なテストの前処理、後処理を記述したもの
Rule前処理 → Before → Test → After → Rule後処理の順で動く

動作検証

package com.mycompany.sandbox;

import org.junit.After;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

public class RuleExamTest {

    @Rule
    public TestRule myTestRule = new TestRule() {
        @Override
        public Statement apply(final Statement base, final Description desc) {
            return new Statement() {
                @Override
                public void evaluate() throws Throwable {
                    System.out.println("RULE PRE PROCESS");
                    base.evaluate();
                    System.out.println("RULE POST PROCESS");
                }
            };
        }
    };
    
    @Before
    public void setUp() {
        System.out.println("BEFORE");
    }
    
    @After
    public void tearDown() {
        System.out.println("AFTER");
    }
    
    @Test
    public void test1() {
        System.out.println("TEST1");
    }
    
    @Test
    public void test2() {
        System.out.println("TEST2");
    }
}

------------- Standard Output ---------------
RULE PRE PROCESS
BEFORE
TEST1
AFTER
RULE POST PROCESS
RULE PRE PROCESS
BEFORE
TEST2
AFTER
RULE POST PROCESS
------------- ---------------- ---------------

↑

JUnit 4 標準のルール †

http://javasourcecode.org/html/open-source/junit/junit-4.10/org/junit/rules/TestRule.html

ErrorCollector?: collect multiple errors in one test method
ExpectedException?: make flexible assertions about thrown exceptions
ExternalResource?: start and stop a server, for example
TemporaryFolder?: create fresh files, and delete after test
TestName?: remember the test name for use during the method
TestWatcher?: add logic at events during method execution
Timeout: cause test to fail after a set time
Verifier: fail test if object state ends up incorrect

↑

System Rules †

http://stefanbirkner.github.com/system-rules/

System 系のメソッドに関するルール
- System.getProperty(…)
- System.setProperty(…)
- System.exit(…)
- System.getSecurityManager?()
- System.err, System.out, System.in
Maven プロジェクトなら pom.xml に依存関係を定義するだけ使える
JUnit 4.9 以上必須
main() のテストで、終了コード(System.exit(…)) の検証はよく使う

↑

Rule の適用順序を明示したい (RuleChain?) †

RuleChain?.outerRule(rule1).around(rule2).around(rule3)...
rule1, rule2, rule3, ... の順に実行される

動作検証

package com.mycompany.sandbox;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExternalResource;
import org.junit.rules.RuleChain;
import org.junit.rules.TestRule;

public class RuleChainExamTest {

    @Rule
    public TestRule chain 
        = RuleChain
            .outerRule(new MyRule("1"))
            .around(new MyRule("2"));

    @Test
    public void test() {
        System.out.println("TEST");
    }
    
    class MyRule extends ExternalResource {
        
        private String pId;
        
        public MyRule(String id) {
            pId = id;
        }
        
        @Override
        public void before() throws Exception {
            System.out.println("BEFORE " + pId);
        }
        @Override
        public void after() {
            System.out.println("AFTER" + pId);
        }
    }
}

------------- Standard Output ---------------
BEFORE 1
BEFORE 2
TEST
AFTER2
AFTER1
------------- ---------------- ---------------

↑

テストクラスで一度だけ実行される前処理・後処理 (@ClassRule?) †

@AfterClass? / @BeforeClass? の Rule 版
アクセス制御子が、public static になることに注意

動作検証

package com.mycompany.sandbox;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExternalResource;
import org.junit.rules.TestRule;

public class ClassRuleExamTest {

    @ClassRule
    public static TestRule myTestClassRule = new ExternalResource() {
        @Override
        public void before() throws Exception {
            System.out.println("CLASS RULE BEFORE");
        }
        @Override
        public void after() {
            System.out.println("CLASS RULE AFTER");
        }
    };
    
    @Rule
    public TestRule myTestRule = new ExternalResource() {
        @Override
        public void before() throws Exception {
            System.out.println("RULE BEFORE");
        }
        @Override
        public void after() {
            System.out.println("RULE AFTER");
        }
    };
    
    @BeforeClass
    public static void setUpClass() {
        System.out.println("CLASS BEFORE");
    }
    
    @AfterClass
    public static void tearDownClass() {
        System.out.println("CLASS AFTER");
    }
    
    @Before
    public void setUp() {
        System.out.println("BEFORE");
    }
    
    @After
    public void tearDown() {
        System.out.println("AFTER");
    }
    
    @Test
    public void test1() {
        System.out.println("TEST1");
    }
    
    @Test
    public void test2() {
        System.out.println("TEST2");
    }
}

------------- Standard Output ---------------
CLASS RULE BEFORE
CLASS BEFORE
RULE BEFORE
BEFORE
TEST1
AFTER
RULE AFTER
RULE BEFORE
BEFORE
TEST2
AFTER
RULE AFTER
CLASS AFTER
CLASS RULE AFTER
------------- ---------------- ---------------

↑

Description からテストメソッドの情報を得る †

例 : Windows 環境では動くが CI サーバ(Linux)上で動かないときにテストを抑止するためのアノテーションを作る

package com.mycompany.sandbox;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface CI {

    public enum DO {EXEC, IGNORE};
    
    public DO value(); 
}

CIアノテーションを使ってテストクラス

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package com.mycompany.sandbox;

import com.mycompany.sandbox.CI.DO;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;

/**
 *
 * @author atsushi
 */
public class RuleDescTest {

    @Rule
    public TestRule myTestRule = new TestRule() {
        @Override
        public Statement apply(final Statement base, final Description desc) {
                        
            System.out.println(desc.getTestClass().getName() + "#" + desc.getMethodName());
            
            CI ci = desc.getAnnotation(CI.class);
            System.out.println("IF THIS RUN ON CI:" + ci.value());
                
            return new Statement() {
                @Override
                public void evaluate() throws Throwable {
                    base.evaluate();
                }
            };
        }
    };
    
    @Test
    @CI(DO.EXEC)
    public void test() {
        System.out.println("TEST");
    }
}

実行結果

------------- Standard Output ---------------
com.mycompany.sandbox.RuleDescTest#test
IF THIS RUN ON CI:EXEC
TEST
------------- ---------------- ---------------

Java#xUNIT

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MenuBar

Rule とは？ †

JUnit 4 標準のルール †

System Rules †

Rule の適用順序を明示したい (RuleChain?) †

テストクラスで一度だけ実行される前処理・後処理 (@ClassRule?) †

Description からテストメソッドの情報を得る †