non input system properties for test tasks

build.gradle

tasks.withType(Test).configureEach { Test testTask ->

        def nonInputs = new InconsequentialSystemProperty()
        testTask.jvmArgumentProviders.add(nonInputs)
        def nonInputSystemProperty = { String key, value ->
            nonInputs.props.put(key, value)
        }

        testTask.extensions.extraProperties.set("nonInputSystemProperty", nonInputSystemProperty)

}

class InconsequentialSystemProperty implements CommandLineArgumentProvider, Named {

    final Map<String, Object> props = [:]

    @Override
    Iterable<String> asArguments() {
        props.collect { key, value -> "-D${key}=${value}".toString() }
    }

    @Override
    String getName() {
        "inconsequentialSystemProperties"
    }
    
}

usage

// example usage
apply plugin:'java-libary'

test {
   //Use TMPDIR as set on TeamCity
   nonInputSystemProperty "java.io.tmpdir", System.getenv('TMPDIR') ?: System.getProperty("java.io.tmpdir")
}