Fixture Monkey 0.4.x

warning

As of May 2024, this post is no longer valid. Instead, please refer to Making Testing Easy and Convenient with Fixture Monkey.

Overview

With the update to FixtureMonkey version 0.4.x, there have been significant changes in functionality. It has only been a month since the previous post¹, and there have been many modifications (ㅠ) which was a bit overwhelming, but taking comfort in the active community, I am writing a new post reflecting the updated features.

Changes

LabMonkey

An experimental feature has been added as an instance.

LabMonkey inherits from FixtureMonkey and supports existing features while adding several new methods. The overall usage is similar, so it seems that using LabMonkey instead of FixtureMonkey would be appropriate. It is said that after version 1.0.0, the functionality of LabMonkey will be deprecated, and the same features will be provided by FixtureMonkey.

private final LabMonkey fixture = LabMonkey.create();

Change in Object Creation Method

The responsibility has shifted from ArbitraryGenerator to ArbitraryIntrospector.

Record Support

Now, you can also create Record through FixtureMonkey.

public record LottoRecord(int number) {}

class LottoRecordTest {

    private final LabMonkey fixture = LabMonkey.labMonkeyBuilder()
            .objectIntrospector(ConstructorPropertiesArbitraryIntrospector.INSTANCE)
            .build();

    @Test
    void shouldBetween1to45() {
        LottoRecord lottoRecord = fixture.giveMeOne(LottoRecord.class);

        System.out.println("lottoRecord: " + lottoRecord);

        assertThat(lottoRecord).isNotNull();
    }
}

lottoRecord: LottoRecord[number=-6]

By using ConstructorPropertiesArbitraryIntrospector to create objects, you can create Record objects. In version 0.3.x, the ConstructorProperties annotation was required, but now you don't need to make changes to the production code, which is quite a significant change.

In addition, various Introspectors exist to support object creation in a way that matches the shape of the object.

Plugin

private final LabMonkey fixture = LabMonkey.labMonkeyBuilder()
    .objectIntrospector(ConstructorPropertiesArbitraryIntrospector.INSTANCE)
    .plugin(new JavaxValidationPlugin())
    .build();

Through the fluent API plugin(), you can easily add plugins. By adding JavaxValidationPlugin, you can apply Java Bean Validation functionality to create objects.

It seems like a kind of decorator pattern, making it easier to develop and apply various third-party plugins.

public record LottoRecord(
        @Min(1)
        @Max(45)
        int number
) {
    public LottoRecord {
        if (number < 1 || number > 45) {
            throw new IllegalArgumentException("The lotto number must be between 1 and 45.");
        }
    }
}

@RepeatedTest(100)
void shouldBetween1to45() {
    LottoRecord lottoRecord = fixture.giveMeOne(LottoRecord.class);

    assertThat(lottoRecord.number()).isBetween(1, 45);
}

Conclusion

Most of the areas that were mentioned as lacking in the previous post have been improved, and I am very satisfied with using it. But somehow, the documentation² seems a bit lacking compared to before...

Reference

Footnotes

1. FixtureMonkey 0.3.0 - Object Creation Strategy ↩

2. FixtureMonkey ↩