[Kotlin] Recursive non-null generation for Kotlin nullable types?

[gerardbosch]

Hi there!

I'm using the Kotlin plugin for FixtureMonkey. I would like to configure it so that never produces null values and recursively, even for Kotlin nullable types like String?.

Is that possible? I tried using a builder with FixtureMonkeyBuilder.defaultNotNull(true), but I see that this does not take effect in Kotlin, as I guess it honors the nullability expressed through Kotlin types and that this setting is mostly for Java.

Could someone confirm? Is that possible to enforce non-null generation on nullable types?

Thanks! 🙂

[gerardbosch]

For anyone interested I found the way to configure it. Though the code is in Kotlin, it works for both Kotlin and Java complex nested objects:

  /**
   * Generates a FixtureMonkey builder for the specified type, using the FixtureMonkey instance configured for Kotlin.
   *
   * @param noNulls If true, the generated instance fields will not contain any null values (recursive). Defaults to
   *     false as the option makes more sense for Java objects.
   * @return A test fixture builder that allows to customize the generated object.
   */
  inline fun <reified A> fixtBuilder(noNulls: Boolean = false)  =
    fixtMonkeyBuilder
      //.defaultNotNull(noNulls) // <-- this is not honored in Kotlin nullable types, e.g. String?
      .defaultNullInjectGenerator { if (noNulls) NOT_NULL_INJECT else DEFAULT_NULL_INJECT }
      .build()
      .giveMeBuilder<A>()

  /**
   * A FixtureMonkey builder configured for Kotlin. The builder can be customized for specific needs, such as
   * registering specific subtype generation via `InterfacePlugin`.
   *
   * Optionally, you can install the IntelliJ plugin 'Fixture Monkey Helper' to get enhanced DX.
   */
  val fixtMonkeyBuilder: FixtureMonkeyBuilder = FixtureMonkey.builder()
    .plugin(KotlinPlugin())
    .useExpressionStrictMode() // runtime failure if string expressions are not valid

Test code:

class FixtureMonkeyTest {

  private data class ComplexObject(
    val nullableString: String?,
    val nullableNestedObject: NestedObject?,
  ) {
    private data class NestedObject(
      val nestedNullableString: String?,
    )
  }

  @RepeatedTest(10)
  fun `should generate complex objects without null fields recursively`() {

    val complexObject = fixtBuilder<ComplexObject>(true)
      .sample()

    assertThat(complexObject)
      .isNotNull
      .hasNoNullFieldsOrProperties()
      .usingRecursiveAssertion()
      .hasNoNullFields()
  }

}

[seongahjo]

Hello, sorry for late response.

It could be done by using the .plugin(KotlinPlugin()) as well.

Thank you.

[gerardbosch]

Hi, thanks for your answer! I'm already using the Kotlin plugin (I mention that on the original message 🙂), but I still had to define the .defaultNullInjectGenerator() - Cheers

[gerardbosch]

EDIT: I updated the snippet above to reflect that. Is that correct?