Compare 2 objects ignoring null values

Question

The project uses TestNg, Java11, Spring test

I am writing testNG tests for API I have a java object that has this kind of stucture:

class Object1
    private Object2 o2;
    private List<Object3> o3;

Where Object2 is not only composed of primitive attributes.

I would like to test if 2 Object1 are equals with these rules:

if actual o2 is null, don't fail even if the other o2 is not
if actual o3 is null or empty, don't fail even if the other o3 is not
if actual o3 is not null nor empty, compare only non null Object3 fields

To sum up, I would like to assert that 2 objects are the same, ignoring null fields recursively.

I could do it

assertThat(actual).usingRecursiveComparison().ignoringActualNullFields().isEqualTo(other);

but the recursive null fields are not ignored.

How can I fix this?

score 0 · Answer 1 · answered May 08 '20 at 03:15

0

You can also ignore expected null fields..

Can you also provide a simple test to reproduce the issue? Feel free to raise an issue in https://github.com/joel-costigliola/assertj-core/issues

answered May 08 '20 at 03:15

Joel Costigliola

6,308
27
35

score 0 · Answer 2 · answered May 09 '20 at 15:32

0

For me following code worked:

public class SocialLink {
    private String platform;
    private String link;
}

SocialLink obj1 = new SocialLink("Facebook", null);
SocialLink obj2 = new SocialLink("Facebook", null);

assertThat(obj1).isEqualToIgnoringNullFields(obj2);

answered May 09 '20 at 15:32

iamcrypticcoder

2,609
4
27
50

Thanks for the reply. I used this for other object but here I have a list of custom pojo, I is not as easy of this – marie May 11 '20 at 07:50

marie · Accepted Answer · 2020-06-04T12:24:48.403

I finally created my own asserts like this:

import org.assertj.core.api.AbstractAssert;
import org.assertj.core.api.Assertions;

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

public class Object1Assert extends AbstractAssert<Object1Assert, Object1> {

    public Object1Assert isEqualTo(Object1 other) {

        // specially for null
        if(actual == other) {return this;}

        if(actual.getObject2() != null) {
            Assertions.assertThat(other.getObject2()).isEqualToIgnoringNullFields(actual.getObject2());
        }

        if(actual.getObject3() != null) {
            for(Object3 object3 : actual.getObject3()) {
                my.package.Assertions.assertThat(object3).isIn(other.getObject3());
            }
        }
        // return the current assertion for method chaining
        return this;
    }

    public Object1Assert(Object1 actual) {
        super(actual, Object1Assert.class);
    }

    public static Object1Assert assertThat(Object1 actual) {
        return new Object1Assert(actual);
    }

}


public class Assertions {

    public static Object3Assert assertThat(Object3 actual) {
        return new Object3Assert(actual);
    }
}

public class Object3Assert extends AbstractAssert<Object3Assert, Object3> {

    public Object3Assert isIn(List<Object3> others) {
        List<String> otherStringIds = others.stream().map(Object3::getStringId).collect(Collectors.toList());
        Assertions.assertThat(otherStringIds).isNotEmpty();
        Assertions.assertThat(actual.getStringId()).isIn(otherStringIds);
        for (Object3 otherObject3 : others) {
            if(actual.getStringId().equalsIgnoreCase(otherObject3.getStringId())) {
                Assertions.assertThat(otherObject3).usingComparatorForType(Comparators.bigDecimalComparator, BigDecimal.class).isEqualToIgnoringNullFields(actual);
            }
        }
        // return the current assertion for method chaining
        return this;
    }

    public Object3Assert(Object3 actual) {
        super(actual, Object3Assert.class);
    }

    public static Object3Assert assertThat(Object3 actual) {
        return new Object3Assert(actual);
    }

}

I created this class for each type I needed with this tutorial https://www.baeldung.com/assertj-custom-assertion

In order to make this a really helpful for future readers, why not give a small code snippet with some dummy classes and your assert? — GhostCat, Jun 04 '20 at 07:58
I edited the answer to add more code and the tutorial I followed — marie, Jun 04 '20 at 12:26

Compare 2 objects ignoring null values

3 Answers3