test: refactor and extract util for asserting on bytecode version (#2072)

Part of
#1699.

Author: krzema12

github-workflows-kt/build.gradle.kts

@@ -31,6 +31,7 @@ dependencies {
     // Needed to use the right version of the compiler for the libraries that depend on it.
     testImplementation(kotlin("compiler"))
     testImplementation(kotlin("reflect"))
+    testImplementation(projects.testUtils)
 
     // GitHub action bindings
     testImplementation("actions:checkout:v4")

github-workflows-kt/src/test/kotlin/io/github/typesafegithub/workflows/JavaBytecodeVersionTest.kt

@@ -1,29 +1,15 @@
 package io.github.typesafegithub.workflows
 
 import io.github.typesafegithub.workflows.domain.Workflow
+import io.github.typesafegithub.workflows.testutils.JdkVersionToBytecodeVersion.JDK_11
+import io.github.typesafegithub.workflows.testutils.shouldHaveBytecodeVersion
 import io.kotest.core.spec.style.FunSpec
-import io.kotest.matchers.shouldBe
-import java.io.DataInputStream
 
 class JavaBytecodeVersionTest :
     FunSpec(
         {
             test("library is built with desired Java bytecode version") {
-                Workflow::class.java.classLoader
-                    .getResourceAsStream(
-                        "io/github/typesafegithub/workflows/domain/Workflow.class",
-                    )!!
-                    .use { inputStream ->
-                        val dataInputStream = DataInputStream(inputStream)
-                        require(dataInputStream.readInt() == 0xCAFEBABE.toInt()) { "Invalid class header" }
-                        val minor = dataInputStream.readUnsignedShort()
-                        val major = dataInputStream.readUnsignedShort()
-
-                        // Corresponds to JDK 11
-                        // See https://javaalmanac.io/bytecode/versions/
-                        major shouldBe 55
-                        minor shouldBe 0
-                    }
+                Workflow::class shouldHaveBytecodeVersion JDK_11
             }
         },
     )

settings.gradle.kts

@@ -10,6 +10,7 @@ include(
     "jit-binding-server",
     "shared-internal",
     "code-generator",
+    "test-utils",
 )
 
 plugins {

test-utils/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+    buildsrc.convention.`kotlin-jvm`
+}
+
+dependencies {
+    implementation(platform("io.kotest:kotest-bom:5.9.1"))
+    implementation("io.kotest:kotest-assertions-core")
+    implementation("io.kotest:kotest-common")
+}

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

@@ -0,0 +1,22 @@
+package io.github.typesafegithub.workflows.testutils
+
+import io.kotest.matchers.shouldBe
+import io.kotest.mpp.qualifiedNameOrNull
+import java.io.DataInputStream
+import kotlin.reflect.KClass
+
+infix fun KClass<*>.shouldHaveBytecodeVersion(expectedVersion: String) {
+    this::class.java.classLoader
+        .getResourceAsStream(
+            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
+        }
+}

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

@@ -0,0 +1,8 @@
+package io.github.typesafegithub.workflows.testutils
+
+/**
+ * See https://javaalmanac.io/bytecode/versions/
+ */
+object JdkVersionToBytecodeVersion {
+    const val JDK_11 = "55.0"
+}