test: add test for bytecode version of bindings (#2073)

Part of
#1699.

Author: krzema12

maven-binding-builder/build.gradle.kts

@@ -10,4 +10,6 @@ dependencies {
     implementation("io.github.oshai:kotlin-logging:7.0.13")
 
     runtimeOnly(projects.githubWorkflowsKt)
+
+    testImplementation(projects.testUtils)
 }

maven-binding-builder/src/main/kotlin/io/github/typesafegithub/workflows/mavenbinding/JarBuilding.kt

@@ -15,16 +15,19 @@ import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler
 import org.jetbrains.kotlin.config.Services
 import java.io.ByteArrayOutputStream
 import java.io.PrintStream
+import java.nio.file.Files
 import java.nio.file.Path
 import kotlin.io.path.Path
 import kotlin.io.path.createParentDirectories
 import kotlin.io.path.createTempDirectory
 import kotlin.io.path.div
 import kotlin.io.path.writeText
+import kotlin.streams.asSequence
 
 internal data class Jars(
     val mainJar: () -> ByteArray,
     val sourcesJar: () -> ByteArray,
+    val randomClassFile: () -> ByteArray,
     val typingActualSource: TypingActualSource?,
 )
 
@@ -34,9 +37,14 @@ internal fun ActionCoords.buildJars(): Jars? {
             if (it.isEmpty()) return null
         }
 
-    val mainJar by lazy {
+    fun prepareJarContents(): Pair<Path, Path> {
         val (sourceFilePaths, compilationInputDir) = binding.prepareDirectoryWithSources()
         val pathWithJarContents = compileBinding(sourceFilePaths = sourceFilePaths)
+        return Pair(compilationInputDir, pathWithJarContents)
+    }
+
+    val mainJar by lazy {
+        val (compilationInputDir, pathWithJarContents) = prepareJarContents()
         val mainJarByteArrayOutputStream = ByteArrayOutputStream()
         mainJarByteArrayOutputStream.createZipFile(pathWithJarContents)
         pathWithJarContents.toFile().deleteRecursively()
@@ -52,9 +60,22 @@ internal fun ActionCoords.buildJars(): Jars? {
         sourcesJarByteArrayOutputStream.toByteArray()
     }
 
+    // Used for testing
+    val randomClassFile by lazy {
+        val (_, pathWithJarContents) = prepareJarContents()
+        val firstClassFile =
+            Files
+                .walk(pathWithJarContents)
+                .asSequence()
+                .filter { Files.isRegularFile(it) && it.fileName.toString().endsWith(".class") }
+                .first()
+        firstClassFile.toFile().readBytes()
+    }
+
     return Jars(
         mainJar = { mainJar },
         sourcesJar = { sourcesJar },
+        randomClassFile = { randomClassFile },
         typingActualSource = binding.firstNotNullOfOrNull { it.typingActualSource },
     )
 }

maven-binding-builder/src/test/kotlin/io/github/typesafegithub/workflows/mavenbinding/JavaBytecodeVersionTest.kt

@@ -0,0 +1,17 @@
+package io.github.typesafegithub.workflows.mavenbinding
+
+import io.github.typesafegithub.workflows.actionbindinggenerator.domain.ActionCoords
+import io.github.typesafegithub.workflows.testutils.JdkVersionToBytecodeVersion.JDK_8
+import io.github.typesafegithub.workflows.testutils.shouldHaveBytecodeVersion
+import io.kotest.core.spec.style.FunSpec
+
+class JavaBytecodeVersionTest :
+    FunSpec(
+        {
+            test("bindings are built with desired Java bytecode version") {
+                val actionCoords = ActionCoords("actions", "setup-java", "v3")
+                val jars = actionCoords.buildJars()!!
+                jars.randomClassFile() shouldHaveBytecodeVersion JDK_8
+            }
+        },
+    )

test-utils/src/main/kotlin/io/github/typesafegithub/workflows/testutils/JavaBytecodeUtils.kt

@@ -2,7 +2,9 @@ package io.github.typesafegithub.workflows.testutils
 
 import io.kotest.matchers.shouldBe
 import io.kotest.mpp.qualifiedNameOrNull
+import java.io.ByteArrayInputStream
 import java.io.DataInputStream
+import java.io.InputStream
 import kotlin.reflect.KClass
 
 infix fun KClass<*>.shouldHaveBytecodeVersion(expectedVersion: String) {
@@ -11,12 +13,19 @@ infix fun KClass<*>.shouldHaveBytecodeVersion(expectedVersion: String) {
             this.qualifiedNameOrNull()!!.replace(".", "/") + ".class",
         )!!
         .use { inputStream ->
-            val dataInputStream = DataInputStream(inputStream)
-            require(dataInputStream.readInt() == 0xCAFEBABE.toInt()) { "Invalid class header" }
-            val minor = dataInputStream.readUnsignedShort()
-            val major = dataInputStream.readUnsignedShort()
-
-            val actualVersion = "$major.$minor"
-            actualVersion shouldBe expectedVersion
+            inputStream shouldHaveBytecodeVersion expectedVersion
         }
 }
+
+infix fun ByteArray.shouldHaveBytecodeVersion(expectedVersion: String) =
+    ByteArrayInputStream(this) shouldHaveBytecodeVersion expectedVersion
+
+private infix fun InputStream.shouldHaveBytecodeVersion(expectedVersion: String) {
+    val dataInputStream = DataInputStream(this)
+    require(dataInputStream.readInt() == 0xCAFEBABE.toInt()) { "Invalid class header" }
+    val minor = dataInputStream.readUnsignedShort()
+    val major = dataInputStream.readUnsignedShort()
+
+    val actualVersion = "$major.$minor"
+    actualVersion shouldBe expectedVersion
+}

test-utils/src/main/kotlin/io/github/typesafegithub/workflows/testutils/JdkVersionToBytecodeVersion.kt

@@ -4,5 +4,6 @@ package io.github.typesafegithub.workflows.testutils
  * See https://javaalmanac.io/bytecode/versions/
  */
 object JdkVersionToBytecodeVersion {
+    const val JDK_8 = "52.0"
     const val JDK_11 = "55.0"
 }