Unit testing with Java 8 features

I just wanted to share something I discovered that might help others. I wanted to write parameterized tests using Stream.of() and Arguments.of(). Those obviously require a Java 8+ build target. You can do the following:

// in root build.gradle
allprojects {
    // We need this to use certain features of JUnit5 (such as calling static methods on interfaces)
    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).matching { "$it".contains("UnitTest") }.all {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8

        kotlinOptions {
            jvmTarget = '1.8'
        }
    }
}

Obviously I’m using Kotlin here. I had an earlier iteration of this script that didn’t have the matching block, and it broke on earlier versions of Android 😃 But this seems to work just fine.

[autonomousapps]

Yup! Removed and still works. Thanks for the heads-up. For posterity, this is the block now:

// in root build.gradle
allprojects {
    // We need this to use certain features of JUnit5 (such as calling static methods on interfaces)
    tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).matching { "$it".contains("UnitTest") }.all {
        kotlinOptions {
            jvmTarget = '1.8'
        }
    }
}

[mannodermaus]

This is now included as part of the new Getting Started guide. Thanks again!