diff --git a/build.sbt b/build.sbt
index 68e69b3f7..2d6179d43 100644
--- a/build.sbt
+++ b/build.sbt
@@ -53,6 +53,10 @@ lazy val commonSettings = Seq(
   licenses := List("Apache 2" -> new URL("http://www.apache.org/licenses/LICENSE-2.0.txt")),
   homepage := Some(url("https://github.com/cognitedata/cdp-spark-datasource")),
   scalacOptions ++= Seq("-Xlint:unused", "-language:higherKinds", "-deprecation", "-feature") ++ (CrossVersion.partialVersion(scalaVersion.value) match {
+    case Some((3, _)) => Seq(
+          "-Wconf:msg=discarded non-Unit value of type org.scalatest.Assertion:s",
+          "-Wconf:msg=discarded non-Unit value of type org.scalatest.compatible.Assertion:s",
+    )
     // We use JavaConverters to remain backwards compatible with Scala 2.12,
     // and to avoid a dependency on scala-collection-compat
     case Some((2, 13)) => Seq(