The setup code for making a pipeline and a demonstration of how it should work inside.

PipelineDSLTest.kt

private lateinit var intToStringPipeline: Pipeline<Int, String>

@Before
fun setUp() {
    intToStringPipeline = CoroutineTestingScope.pipeline() {
        for (number in channel) {
            send { number.toString() }
        }
    }
}