Your first test

All tests will start from using the base class Junisert, to make use of caching and assertion alternatives. If you are familiar with the AssertJ testing library you will be familiar with the fluent testing technique, chaining methods to set up several tests quickly after each other.

Table of Contents

• Plain mutable object
• Plain immutable object

Plain mutable object

Given mutable class:

public class MutableObject {
    private String sender;
    private String reciever;
    private List<String> labels;
    private byte[] attachment;

    public String getSender() {
        return sender;
    }

    public void setSender(String sender) {
        this.sender = sender;
    }

    public String getReciever() {
        return reciever;
    }

    public void setReciever(String reciever) {
        this.reciever = reciever;
    }

    public List<String> getLabels() {
        return labels;
    }

    public void setLabels(List<String> labels) {
        this.labels = labels;
    }

    public byte[] getAttachment() {
        return attachment;
    }

    public void setAttachment(byte[] attachment) {
        this.attachment = attachment;
    }

    @Override
    public boolean equals(Object object) {
        if (this == object) return true;
        if (object == null || getClass() != object.getClass()) return false;
        MutableObject that = (MutableObject) object;
        return Objects.equals(sender, that.sender) && Objects.equals(reciever, that.reciever)
                && Objects.equals(labels, that.labels) && Arrays.equals(attachment, that.attachment);
    }

    @Override
    public int hashCode() {
        int result = Objects.hash(sender, reciever, labels);
        result = 31 * result + Arrays.hashCode(attachment);
        return result;
    }

    @Override
    public String toString() {
        return "MutableObject{" +
                "sender='" + sender + '\'' +
                ", reciever='" + reciever + '\'' +
                ", labels=" + labels +
                ", attachment=" + Arrays.toString(attachment) +
                '}';
    }
}

Test that it’s well implemented:

class MutableObjectTest {
    @Test
    void isWellImplemented() {
        Junisert.assertThatPojo(MutableObject.class).isWellImplemented();
    }
}

Checking that it’s well implemented is a convenience way of checking proper structure. It’s the same as using the following testing technique:

class MutableObjectTest {
    @Test
    void isWellImplemented() {
        Junisert.assertThatPojo(MutableObject.class)
                .hasGetters()
                .hasSetters()
                .implementsEqualsAndHashCode()
                .implementsToString();
    }
}

Plain immutable object

Given immutable class:

public class ImmutableObject {
    private final String sender;
    private final String reciever;
    private final List<String> labels;
    private final byte[] attachment;

    public ImmutableObject(String sender, String reciever, List<String> labels, byte[] attachment) {
        this.sender = sender;
        this.reciever = reciever;
        this.labels = labels;
        this.attachment = attachment;
    }

    public String getSender() {
        return sender;
    }

    public String getReciever() {
        return reciever;
    }

    public List<String> getLabels() {
        return labels;
    }

    public byte[] getAttachment() {
        return attachment;
    }

    @Override
    public boolean equals(Object object) {
        if (this == object) return true;
        if (object == null || getClass() != object.getClass()) return false;
        ImmutableObject that = (ImmutableObject) object;
        return Objects.equals(sender, that.sender) && Objects.equals(reciever, that.reciever)
                && Objects.equals(labels, that.labels) && Arrays.equals(attachment, that.attachment);
    }

    @Override
    public int hashCode() {
        int result = Objects.hash(sender, reciever, labels);
        result = 31 * result + Arrays.hashCode(attachment);
        return result;
    }

    @Override
    public String toString() {
        return "ImmutableObject{" +
                "sender='" + sender + '\'' +
                ", reciever='" + reciever + '\'' +
                ", labels=" + labels +
                ", attachment=" + Arrays.toString(attachment) +
                '}';
    }
}

Or record:

public record ImmutableObject(String sender, String reciever, List<String> labels, byte[] attachment) {
}

Test that it’s well implemented the same way, assertion for setters however will be skipped since the properties are read-only:

class ImmutableObjectTest {
   @Test
   void isWellImplemented() {
      Junisert.assertThatPojo(ImmutableObject.class).isWellImplemented();
   }
}