albert's blog: How to Improve Code Coverage After Using Apache Lombok?

2017/08/10

How to Improve Code Coverage After Using Apache Lombok?

Problem
After using Project Lombok, we can find out it help use reduce our boilerplate code.

package albert.practice.lambda;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

import com.google.common.base.Strings;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

public class LambdaTest {

    public List<Person> filterData() {
        List<Person> people = createData();
        return people.stream().filter(p -> p.age >= 35).filter(p -> !Strings.isNullOrEmpty(p.email))
                .collect(Collectors.toList());
    }

    public List<Person> filterDataWithSort() {
        List<Person> people = createData();
        return people.stream().filter(p -> p.age >= 35).sorted((p1, p2) -> (p1.age - p2.age))
                .sorted((p1, p2) -> p2.name.compareTo(p1.name)).collect(Collectors.toList());
    }

    public List<Person> createData() {
        Person ben = new Person("Ben Whittaker", 70, "ben@gmail.com");
        Person jules = new Person("Jules Ostin", 30, "jules@gmail.com");
        Person fiona = new Person("Fiona Farwell", 68, null);
        Person matt = new Person("Matt", 35, "matt@gmail.com");
        
        return Arrays.asList(ben, jules, fiona, matt);
    }

    @Data
    @ToString
    @AllArgsConstructor
    @NoArgsConstructor
    public static class Person {
        private String name;
        private int age;
        private String email;
    }

}

But you will also notice your code coverage rate is down dramatically.

How to improve the code coverage rate?

How-To
Add two dependencies to your pom.xml

<dependencies>
    <dependency>
        <groupId>org.meanbean</groupId>
        <artifactId>meanbean</artifactId>
        <version>2.0.2</version>
    </dependency>

    <dependency>
        <groupId>nl.jqno.equalsverifier</groupId>
        <artifactId>equalsverifier</artifactId>
        <version>2.2.1</version>
        <scope>test</scope>
    </dependency>
</dependencies>

Check the testPersonBean() and testEqualsAndHashCode() in this test case:

package albert.practice.lambda;

import static org.junit.Assert.assertEquals;

import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.meanbean.test.BeanTester;

import albert.practice.lambda.LambdaTest.Person;
import lombok.extern.slf4j.Slf4j;
import nl.jqno.equalsverifier.EqualsVerifier;
import nl.jqno.equalsverifier.Warning;

@Slf4j
public class LambdaUnitTest {

    private LambdaTest lambdaTest = null;

    @Before
    public void setup() {
        lambdaTest = new LambdaTest();
    }

    @Test
    public void testCreateData() {
        List<Person> people = lambdaTest.createData();
        assertEquals(people.size(), 4);
    }

    @Test
    public void testFilterData() {
        List<Person> people = lambdaTest.filterData();
        log.debug("testFilterData = " + people.toString());
        assertEquals(people.size(), 2);
    }

    @Test
    public void testFilterDataWithSort() {
        List<Person> people = lambdaTest.filterDataWithSort();
        log.debug("testFilterDataWithSort = " + people.toString());
        assertEquals(people.size(), 3);
    }

    // Testing getter and setters methods
    @Test
    public void testPersonBean() {
        new BeanTester().testBean(LambdaTest.Person.class);
    }

    // Testing equals() and hashCode()
    @Test
    public void testEqualsAndHashcode() {
        EqualsVerifier.forClass(LambdaTest.Person.class)
                .suppress(Warning.STRICT_INHERITANCE, Warning.NONFINAL_FIELDS).verify();
    }

}