private
    fun minify(artifact: File, keepClasses: Set<String>, jarFile: File): File {
        val tempDirectory = java.nio.file.Files.createTempDirectory(jarFile.name).toFile()
        val classesDir = tempDirectory.resolve("classes")
        val manifestFile = tempDirectory.resolve("MANIFEST.MF")
        val buildReceiptFile = tempDirectory.resolve("build-receipt.properties")

$linesWithEcho

echo Performance tests to be ${action}d in this build
type $performanceTestSplitDirectoryName\$action-$fileNamePostfix
"""

    return {
        script {
            name = "PREPARE_TEST_CLASSES"
            executionMode = BuildStep.ExecutionMode.ALWAYS
            scriptContent = if (os == Os.WINDOWS) windowsScript else unixScript
        }
    }
}

            """
        ) {

            assertHasNoInformation()
            assertHasNoWarning()
            assertHasErrors(

                // Kotlin file-facade classes are ignored by the @since rule
                listOf("Class com.example.SourceKt: Is not annotated with @Incubating."),

                added("Field", "cathedral"),
                added("Method", "SourceKt.foo()"),