[JAVA] Control test order in Junit4 with enumeration

Overview

JUnit does not guarantee the execution order of the methods defined by the @Test annotation.

Therefore, create the following three classes to control the execution order.

• OrderedRunner --Annotation class to be set in the test class
• Order --Annotation class to set in test method
• TestMethod --ʻOrder` enumeration type class that enumerates the setting values of the class

As a process flow, ʻOrderedRunner was added to each test method when executing the test. The flow is to control the execution order by reading the setting value of ʻOrder.

TestMethod.java

public enum TestMethod {
    strArrayIsNullTest,
    strIsNullTest
};

Order.java

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

@Retention(RetentionPolicy.RUNTIME)
public @interface Order {
    TestMethod order();
}

OrderedRunner.java

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;

public class OrderedRunner extends BlockJUnit4ClassRunner {
    public OrderedRunner(Class<?> klass) throws InitializationError  {
        super(klass);
    }

    @Override
    protected List<FrameworkMethod> computeTestMethods() {
        List<FrameworkMethod> list = super.computeTestMethods();
        Collections.sort(list, new Comparator<FrameworkMethod>() {
            @Override
            public int compare(FrameworkMethod f1, FrameworkMethod f2) {
                Order o1 = f1.getAnnotation(Order.class);
                Order o2 = f2.getAnnotation(Order.class);

                if (o1 == null || o2 == null){
                    return -1;
                }
                return o1.order().ordinal() - o2.order().ordinal();
            }
        });
        return list;
    }
}

Practice

Foo.java

public class Foo {
    public static boolean isNull(String[] arg) {
        return arg == null;
    }

    public static boolean isNull(String str) {
        return str == null || str.length() == 0 || str.equals("");
    }
}

FooTest.java

import static org.junit.Assert.*;

import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(OrderedRunner.class)
public class FooTest {

    @Test
    @Order(order=TestMethod.strArrayIsNullTest)
    public void strArrayIsNullTest() {
        String[] arg = {"test"};
        assertFalse(Foo.isNull(arg));
        System.out.println("strArrayIsNullTest OK");
    }

    //Even if you add a test, the order is guaranteed by adding an element to TestMethod.
    /**
     * @Test
     * @Order(order=TestMethod.reservationsTest)
     * public void reservationsTest();
     */

    @Test
    @Order(order=TestMethod.strIsNullTest)
    public void strIsNullTest() {
        String str = "test";
        assertFalse(Foo.isNull(str));
        System.out.println("strIsNullTest OK");
    }
}

Reference material

• https://qiita.com/kerupani129/items/287b310785e9a0adce06