Add rudimentary script support

Author: tschuchortdev

src/main/kotlin/com/tschuchort/compiletesting/ScriptUtils.kt

@@ -0,0 +1,29 @@
+package com.tschuchort.compiletesting
+
+
+import org.jetbrains.kotlin.load.kotlin.PackagePartClassUtils
+import org.jetbrains.kotlin.name.Name
+import java.net.URLClassLoader
+
+fun KotlinCompilation.Result.runCompiledScript(
+    fileName: String,
+    args: List<String> = emptyList(),
+    classLoader: ClassLoader? = Thread.currentThread().contextClassLoader
+) {
+    fun String.removeKotlinFileSuffix() = removeSuffix(".kt").removeSuffix(".kts")
+
+    val scriptClassName = Name.identifier(
+        PackagePartClassUtils.getFilePartShortName(fileName.removeKotlinFileSuffix())
+    ).identifier.removeSuffix("Kt")
+
+    val scriptClassLoader = URLClassLoader(arrayOf(outputDirectory.toURI().toURL()), classLoader)
+
+    val scriptClass = try {
+        scriptClassLoader.loadClass(scriptClassName)
+    } catch (e: ClassNotFoundException) {
+        throw IllegalArgumentException("Could not load script class for given filename $fileName", e)
+    }
+
+    scriptClass.getConstructor(Array<String>::class.java).newInstance(args.toTypedArray())
+}
+

src/main/kotlin/com/tschuchort/compiletesting/Utils.kt

@@ -1,9 +1,10 @@
 package com.tschuchort.compiletesting
 
-import java.io.File
-import java.io.IOException
+import okio.Buffer
+import java.io.*
 import java.net.URL
 import java.net.URLClassLoader
+import java.nio.charset.Charset
 import java.nio.file.*
 import java.nio.file.attribute.BasicFileAttributes
 import javax.lang.model.SourceVersion
@@ -83,4 +84,17 @@ internal inline fun <T> withSystemProperties(properties: Map<String, String>, f:
                 System.setProperty(key, value)
         }
     }
+}
+
+internal inline fun <R> withSystemOut(stream: PrintStream, crossinline f: () -> R): R {
+    System.setOut(stream)
+    val ret = f()
+    System.setOut(PrintStream(FileOutputStream(FileDescriptor.out)))
+    return ret
+}
+
+internal inline fun <R> captureSystemOut(crossinline f: () -> R): Pair<R, String> {
+    val systemOutBuffer = Buffer()
+    val ret = withSystemOut(PrintStream(systemOutBuffer.outputStream()), f)
+    return Pair(ret, systemOutBuffer.readString(Charset.defaultCharset()))
 }

src/test/kotlin/com/tschuchort/compiletesting/KotlinCompilationTests.kt

@@ -2,11 +2,14 @@ package com.tschuchort.compiletesting
 
 import org.assertj.core.api.Assertions.assertThat
 import com.tschuchort.compiletesting.KotlinCompilation.ExitCode
+import okio.Buffer
 import org.assertj.core.api.Assertions.fail
 import org.junit.Rule
 import org.junit.Test
 import org.junit.rules.TemporaryFolder
-import java.io.File
+import java.io.FileDescriptor
+import java.io.FileOutputStream
+import java.io.PrintStream
 import javax.annotation.processing.AbstractProcessor
 import javax.annotation.processing.RoundEnvironment
 import javax.lang.model.element.TypeElement
@@ -588,6 +591,42 @@ class KotlinCompilationTests {
 		assertClassLoadable(result, "${KotlinTestProcessor.GENERATED_PACKAGE}.${KotlinTestProcessor.GENERATED_JAVA_CLASS_NAME}")
 	}
 
+	@Test
+	fun `Can execute Kotlinscript`() {
+	    val kSource = SourceFile.new("Kscript.kts", """
+    println("hello script")
+""".trimIndent())
+
+		val result = defaultCompilerConfig().apply {
+			sources = listOf(kSource)
+		}.compile()
+
+		val (ret, sysOut) = captureSystemOut {
+			result.runCompiledScript("Kscript")
+		}
+
+		assertThat(sysOut).contains("hello script")
+	}
+
+	@Test
+	fun `Kotlinscript receives command line arguments`() {
+		val kSource = SourceFile.new("Kscript.kts", """
+    println(args[0] + " " + args[1])
+""".trimIndent())
+
+		val result = defaultCompilerConfig().apply {
+			sources = listOf(kSource)
+		}.compile()
+
+		assertThat(result.exitCode).isEqualTo(ExitCode.OK)
+
+		val (_, sysOut) = captureSystemOut {
+			result.runCompiledScript("Kscript", args = listOf("arg0", "arg1"))
+		}
+
+		assertThat(sysOut).contains("arg0 arg1")
+	}
+
 	private fun defaultCompilerConfig(): KotlinCompilation {
 		return KotlinCompilation().apply {
 			workingDir = temporaryFolder.root