diff --git a/docs/kotlin-plugins/README.md b/docs/kotlin-plugins/README.md
index 5b824b01d..2571a9233 100644
--- a/docs/kotlin-plugins/README.md
+++ b/docs/kotlin-plugins/README.md
@@ -77,6 +77,7 @@ automatically configure additional tasks for bundling the shadowed JAR for its `
     }
 
     kotlin {
+      @Suppress("OPT_IN_USAGE")
       jvm().mainRun {
         // Optionally, set the main class for `runJvm`.
         mainClass = "myapp.MainKt"
diff --git a/src/testKit/kotlin/com/github/jengelman/gradle/plugins/shadow/testkit/GradleRunner.kt b/src/testKit/kotlin/com/github/jengelman/gradle/plugins/shadow/testkit/GradleRunner.kt
index 17ef5b3ff..9a2071074 100644
--- a/src/testKit/kotlin/com/github/jengelman/gradle/plugins/shadow/testkit/GradleRunner.kt
+++ b/src/testKit/kotlin/com/github/jengelman/gradle/plugins/shadow/testkit/GradleRunner.kt
@@ -41,6 +41,8 @@ val commonGradleArgs =
     "--build-cache",
     "--stacktrace",
     "--warning-mode=fail",
+    "-Dorg.gradle.kotlin.dsl.allWarningsAsErrors=true",
+    "-Dorg.gradle.tooling.parallel=true",
     // https://docs.gradle.org/current/userguide/configuration_cache.html#config_cache:usage:parallel
     "-Dorg.gradle.configuration-cache.parallel=true",
     // https://docs.gradle.org/current/userguide/isolated_projects.html#how_do_i_use_it