diff --git a/src/funcTest/groovy/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.groovy b/src/funcTest/groovy/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.groovy
deleted file mode 100644
index 18e4331da..000000000
--- a/src/funcTest/groovy/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.groovy
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.github.jengelman.gradle.plugins.shadow.util
-
-import com.github.jengelman.gradle.plugins.shadow.util.repo.maven.MavenFileRepository
-import groovy.transform.InheritConstructors
-
-@InheritConstructors
-class AppendableMavenFileRepository extends MavenFileRepository {
-
-    @Override
-    AppendableMavenFileModule module(String groupId, String artifactId, String version = '1.0') {
-        def artifactDir = rootDir.resolve("${groupId.replace('.', '/')}/$artifactId/$version")
-        return new AppendableMavenFileModule(artifactDir, groupId, artifactId, version as String)
-    }
-}
diff --git a/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.kt b/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.kt
new file mode 100644
index 000000000..b0441362b
--- /dev/null
+++ b/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/AppendableMavenFileRepository.kt
@@ -0,0 +1,12 @@
+package com.github.jengelman.gradle.plugins.shadow.util
+
+import com.github.jengelman.gradle.plugins.shadow.util.repo.maven.MavenFileRepository
+import java.io.File
+
+class AppendableMavenFileRepository(rootDir: File) : MavenFileRepository(rootDir) {
+
+  override fun module(groupId: String, artifactId: String, version: String): AppendableMavenFileModule {
+    val artifactDir = rootDir.resolve("${groupId.replace('.', '/')}/$artifactId/$version")
+    return AppendableMavenFileModule(artifactDir, groupId, artifactId, version)
+  }
+}
diff --git a/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/repo/maven/MavenFileRepository.kt b/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/repo/maven/MavenFileRepository.kt
index 42af89739..026ebd8de 100644
--- a/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/repo/maven/MavenFileRepository.kt
+++ b/src/intiTest/kotlin/com/github/jengelman/gradle/plugins/shadow/util/repo/maven/MavenFileRepository.kt
@@ -6,7 +6,7 @@ import java.net.URI
 /**
  * A fixture for dealing with file Maven repositories.
  */
-abstract class MavenFileRepository(private val rootDir: File) : MavenRepository {
+abstract class MavenFileRepository(val rootDir: File) : MavenRepository {
 
   override val uri: URI = rootDir.toURI()