build.sbt

name := "fs2-kafka-test"

version := "0.1"

scalaVersion := "2.12.10"

libraryDependencies ++= Seq(
  "com.ovoenergy" %% "fs2-kafka" % "0.20.2",

  "org.scalatest" %% "scalatest" % "3.0.8" % Test,
)

scalacOptions ++= Seq(
  "-language:higherKinds",
  "-feature",
  "-deprecation",
  "-unchecked",
  "-Ypartial-unification"
)

ProducerSpec.scala

import org.scalatest.WordSpec

import fs2.kafka._
import cats.effect._
import cats.implicits._

class ProducerSpec extends WordSpec {

  "Producer" must {

    "work" in {
      implicit val iocs = IO.contextShift(scala.concurrent.ExecutionContext.global)
      val producerSettings = ProducerSettings[IO, String, String].withBootstrapServers("localhost:9092")
      producerStream(producerSettings)
        .map { producer =>
          val record = ProducerRecords.one(
            ProducerRecord[String, String](
              topic = "pizza-events",
              key = "key",
              value = "message"
            )
          )
          producer.produce(record).flatten
        }
        .compile
        .lastOrError
        .flatten
        .unsafeRunSync()
    }

  }

}