Replace Fabric JUnit hacks with fabric-loader-junit

Also configure some of our common JUnit run configurations via Gradle -
I end up setting these up in every worktree anyway - so let's just do it
once.

build.gradle.kts

@@ -2,7 +2,11 @@
 //
 // SPDX-License-Identifier: MPL-2.0
 
+import cc.tweaked.gradle.JUnitExt
+import net.fabricmc.loom.api.LoomGradleExtensionAPI
+import net.fabricmc.loom.util.gradle.SourceSetHelper
 import org.jetbrains.gradle.ext.compiler
+import org.jetbrains.gradle.ext.runConfigurations
 import org.jetbrains.gradle.ext.settings
 
 plugins {
@@ -38,6 +42,50 @@ githubRelease {
 
 tasks.publish { dependsOn(tasks.githubRelease) }
 
+idea.project.settings.runConfigurations {
+    register<JUnitExt>("Core Tests") {
+        vmParameters = "-ea"
+        moduleName = "${idea.project.name}.core.test"
+        packageName = ""
+    }
+
+    register<JUnitExt>("CraftOS Tests") {
+        vmParameters = "-ea"
+        moduleName = "${idea.project.name}.core.test"
+        className = "dan200.computercraft.core.ComputerTestDelegate"
+    }
+
+    register<JUnitExt>("CraftOS Tests (Fast)") {
+        vmParameters = "-ea -Dcc.skip_keywords=slow"
+        moduleName = "${idea.project.name}.core.test"
+        className = "dan200.computercraft.core.ComputerTestDelegate"
+    }
+
+    register<JUnitExt>("Common Tests") {
+        vmParameters = "-ea"
+        moduleName = "${idea.project.name}.common.test"
+        packageName = ""
+    }
+
+    register<JUnitExt>("Fabric Tests") {
+        val fabricProject = evaluationDependsOn(":fabric")
+        val classPathGroup = fabricProject.extensions.getByType<LoomGradleExtensionAPI>().mods
+            .joinToString(File.pathSeparator + File.pathSeparator) { modSettings ->
+                SourceSetHelper.getClasspath(modSettings, project).joinToString(File.pathSeparator) { it.absolutePath }
+            }
+
+        vmParameters = "-ea -Dfabric.classPathGroups=$classPathGroup"
+        moduleName = "${idea.project.name}.fabric.test"
+        packageName = ""
+    }
+
+    register<JUnitExt>("Forge Tests") {
+        vmParameters = "-ea"
+        moduleName = "${idea.project.name}.forge.test"
+        packageName = ""
+    }
+}
+
 idea.project.settings.compiler.javac {
     // We want ErrorProne to be present when compiling via IntelliJ, as it offers some helpful warnings
     // and errors. Loop through our source sets and find the appropriate flags.

buildSrc/build.gradle.kts

@@ -50,10 +50,11 @@ dependencies {
     implementation(libs.curseForgeGradle)
     implementation(libs.fabric.loom)
     implementation(libs.forgeGradle)
+    implementation(libs.ideaExt)
     implementation(libs.librarian)
     implementation(libs.minotaur)
-    implementation(libs.vineflower)
     implementation(libs.vanillaGradle)
+    implementation(libs.vineflower)
 }
 
 gradlePlugin {

buildSrc/src/main/kotlin/cc/tweaked/gradle/CCTweakedPlugin.kt

@@ -9,6 +9,10 @@ import org.gradle.api.Project
 import org.gradle.api.plugins.JavaPlugin
 import org.gradle.api.plugins.JavaPluginExtension
 import org.gradle.jvm.toolchain.JavaLanguageVersion
+import org.gradle.plugins.ide.idea.model.IdeaModel
+import org.jetbrains.gradle.ext.IdeaExtPlugin
+import org.jetbrains.gradle.ext.runConfigurations
+import org.jetbrains.gradle.ext.settings
 
 /**
  * Configures projects to match a shared configuration.
@@ -21,6 +25,20 @@ class CCTweakedPlugin : Plugin<Project> {
             val sourceSets = project.extensions.getByType(JavaPluginExtension::class.java).sourceSets
             cct.sourceDirectories.add(SourceSetReference.internal(sourceSets.getByName("main")))
         }
+
+        project.plugins.withType(IdeaExtPlugin::class.java) { extendIdea(project) }
+    }
+
+    /**
+     * Extend the [IdeaExtPlugin] plugin's `runConfiguration` container to also support [JUnitExt].
+     */
+    private fun extendIdea(project: Project) {
+        val ideaModel = project.extensions.findByName("idea") as IdeaModel? ?: return
+        val ideaProject = ideaModel.project ?: return
+
+        ideaProject.settings.runConfigurations {
+            registerFactory(JUnitExt::class.java) { name -> project.objects.newInstance(JUnitExt::class.java, name) }
+        }
     }
 
     companion object {

buildSrc/src/main/kotlin/cc/tweaked/gradle/IdeaExt.kt

@@ -0,0 +1,23 @@
+// SPDX-FileCopyrightText: 2023 The CC: Tweaked Developers
+//
+// SPDX-License-Identifier: MPL-2.0
+
+package cc.tweaked.gradle
+
+import org.jetbrains.gradle.ext.JUnit
+import javax.inject.Inject
+
+/**
+ * A version of [JUnit] with a functional [className].
+ *
+ * See [#92](https://github.com/JetBrains/gradle-idea-ext-plugin/issues/92).
+ */
+open class JUnitExt @Inject constructor(nameParam: String) : JUnit(nameParam) {
+    override fun toMap(): MutableMap<String, *> {
+        val map = HashMap(super.toMap())
+        // Should be "class" instead of "className".
+        // See https://github.com/JetBrains/intellij-community/blob/9ba394021dc73a3926f13d6d6cdf434f9ee7046d/plugins/junit/src/com/intellij/execution/junit/JUnitRunConfigurationImporter.kt#L39
+        map["class"] = className
+        return map
+    }
+}

gradle/libs.versions.toml

@@ -45,7 +45,6 @@ rubidium = "0.6.1"
 sodium = "mc1.20-0.4.10"
 
 # Testing
-byteBuddy = "1.14.7"
 hamcrest = "2.2"
 jqwik = "1.7.4"
 junit = "5.10.0"
@@ -97,6 +96,7 @@ slf4j = { module = "org.slf4j:slf4j-api", version.ref = "slf4j" }
 # Minecraft mods
 fabric-api = { module = "net.fabricmc.fabric-api:fabric-api", version.ref = "fabric-api" }
 fabric-loader = { module = "net.fabricmc:fabric-loader", version.ref = "fabric-loader" }
+fabric-junit = { module = "net.fabricmc:fabric-loader-junit", version.ref = "fabric-loader" }
 fabricPermissions = { module = "me.lucko:fabric-permissions-api", version.ref = "fabricPermissions" }
 emi = { module = "dev.emi:emi-xplat-mojmap", version.ref = "emi" }
 iris = { module = "maven.modrinth:iris", version.ref = "iris" }
@@ -114,8 +114,6 @@ rubidium = { module = "maven.modrinth:rubidium", version.ref = "rubidium" }
 sodium = { module = "maven.modrinth:sodium", version.ref = "sodium" }
 
 # Testing
-byteBuddyAgent = { module = "net.bytebuddy:byte-buddy-agent", version.ref = "byteBuddy" }
-byteBuddy = { module = "net.bytebuddy:byte-buddy", version.ref = "byteBuddy" }
 hamcrest = { module = "org.hamcrest:hamcrest", version.ref = "hamcrest" }
 jqwik-api = { module = "net.jqwik:jqwik-api", version.ref = "jqwik" }
 jqwik-engine = { module = "net.jqwik:jqwik-engine", version.ref = "jqwik" }
@@ -135,6 +133,7 @@ errorProne-plugin = { module = "net.ltgt.gradle:gradle-errorprone-plugin", versi
 errorProne-testHelpers = { module = "com.google.errorprone:error_prone_test_helpers", version.ref = "errorProne-core" }
 fabric-loom = { module = "net.fabricmc:fabric-loom", version.ref = "fabric-loom" }
 forgeGradle = { module = "net.minecraftforge.gradle:ForgeGradle", version.ref = "forgeGradle" }
+ideaExt = { module = "gradle.plugin.org.jetbrains.gradle.plugin.idea-ext:gradle-idea-ext", version.ref = "ideaExt" }
 kotlin-plugin = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin", version.ref = "kotlin" }
 librarian = { module = "org.parchmentmc:librarian", version.ref = "librarian" }
 minotaur = { module = "com.modrinth.minotaur:Minotaur", version.ref = "minotaur" }
@@ -154,7 +153,6 @@ vineflower = { module = "io.github.juuxel:loom-vineflower", version.ref = "vinef
 [plugins]
 forgeGradle = { id = "net.minecraftforge.gradle", version.ref = "forgeGradle" }
 githubRelease = { id = "com.github.breadmoirai.github-release", version.ref = "githubRelease" }
-ideaExt = { id = "org.jetbrains.gradle.plugin.idea-ext", version.ref = "ideaExt" }
 kotlin = { id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin" }
 librarian = { id = "org.parchmentmc.librarian.forgegradle", version.ref = "librarian" }
 mixinGradle = { id = "org.spongepowered.mixin", version.ref = "mixinGradle" }

projects/fabric/build.gradle.kts

@@ -87,10 +87,9 @@ dependencies {
     testModImplementation(testFixtures(project(":core")))
     testModImplementation(testFixtures(project(":fabric")))
 
-    testImplementation(libs.byteBuddy)
-    testImplementation(libs.byteBuddyAgent)
     testImplementation(libs.bundles.test)
     testRuntimeOnly(libs.bundles.testRuntime)
+    testRuntimeOnly(libs.fabric.junit)
 
     testFixturesImplementation(testFixtures(project(":core")))
 }

projects/fabric/src/test/java/dan200/computercraft/shared/FabricBootstrap.java

@@ -1,249 +0,0 @@
-// SPDX-FileCopyrightText: 2022 The CC: Tweaked Developers
-//
-// SPDX-License-Identifier: MPL-2.0
-
-package dan200.computercraft.shared;
-
-import com.google.auto.service.AutoService;
-import com.google.common.base.Splitter;
-import com.google.common.io.ByteStreams;
-import net.bytebuddy.agent.ByteBuddyAgent;
-import net.bytebuddy.dynamic.loading.ClassInjector;
-import net.fabricmc.api.EnvType;
-import net.fabricmc.loader.impl.FabricLoaderImpl;
-import net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider;
-import net.fabricmc.loader.impl.game.minecraft.Slf4jLogHandler;
-import net.fabricmc.loader.impl.launch.FabricLauncherBase;
-import net.fabricmc.loader.impl.launch.FabricMixinBootstrap;
-import net.fabricmc.loader.impl.launch.knot.MixinServiceKnot;
-import net.fabricmc.loader.impl.transformer.FabricTransformer;
-import net.fabricmc.loader.impl.util.LoaderUtil;
-import net.fabricmc.loader.impl.util.log.Log;
-import org.junit.jupiter.api.extension.Extension;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.spongepowered.asm.mixin.MixinEnvironment;
-import org.spongepowered.asm.mixin.transformer.IMixinTransformer;
-
-import javax.annotation.Nullable;
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
-import java.lang.instrument.ClassFileTransformer;
-import java.lang.instrument.IllegalClassFormatException;
-import java.lang.instrument.Instrumentation;
-import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
-import java.security.ProtectionDomain;
-import java.util.*;
-import java.util.jar.Manifest;
-import java.util.stream.Collectors;
-
-/**
- * Loads Fabric mods as part of this test run.
- * <p>
- * This sets up a minimalistic {@link FabricLauncherBase}, uses that to load mods, and then acquires an
- * {@link Instrumentation} instance, registering a {@link ClassFileTransformer} to apply mixins and access wideners.
- *
- * @see net.fabricmc.loader.impl.launch.knot.Knot
- */
-@AutoService(Extension.class)
-public class FabricBootstrap implements Extension {
-    private static final Logger LOG = LoggerFactory.getLogger(FabricBootstrap.class);
-
-    public FabricBootstrap() throws ReflectiveOperationException, IOException {
-        Log.init(new Slf4jLogHandler());
-
-        readProperties();
-        {
-            var method = FabricLauncherBase.class.getDeclaredMethod("setProperties", Map.class);
-            method.setAccessible(true);
-            method.invoke(null, new HashMap<>());
-        }
-
-        var provider = new MinecraftGameProvider();
-        if (!provider.locateGame(new BasicLauncher(), new String[0])) {
-            throw new IllegalStateException("Cannot setup game");
-        }
-
-        var loader = FabricLoaderImpl.INSTANCE;
-        loader.setGameProvider(provider);
-        loader.load();
-        loader.freeze();
-        loader.loadAccessWideners();
-
-        FabricMixinBootstrap.init(EnvType.CLIENT, loader);
-        {
-            var method = FabricLauncherBase.class.getDeclaredMethod("finishMixinBootstrapping");
-            method.setAccessible(true);
-            method.invoke(null);
-        }
-
-        IMixinTransformer transformer;
-        {
-            var method = MixinServiceKnot.class.getDeclaredMethod("getTransformer");
-            method.setAccessible(true);
-            transformer = (IMixinTransformer) method.invoke(null);
-        }
-
-        ByteBuddyAgent.install().addTransformer(new ClassTransformer(transformer));
-    }
-
-    private static void readProperties() throws IOException {
-        try (var reader = Files.newBufferedReader(Path.of(".gradle/loom-cache/launch.cfg"))) {
-            var interesting = false;
-
-            String line;
-            while ((line = reader.readLine()) != null) {
-                if (line.startsWith(" ") || line.startsWith("\t")) {
-                    if (!interesting) continue;
-
-                    line = line.strip();
-                    var index = line.indexOf('=');
-
-                    if (index >= 0) {
-                        System.setProperty(line.substring(0, index), line.substring(index + 1));
-                    } else {
-                        System.setProperty(line, "");
-                    }
-                } else {
-                    interesting = line.equals("commonProperties") || line.equals("clientProperties");
-                }
-            }
-        }
-    }
-
-    private static final class BasicLauncher extends FabricLauncherBase {
-        private final List<Path> classpath = new ArrayList<>();
-
-        BasicLauncher() {
-            for (var entry : Splitter.on(File.pathSeparatorChar).split(System.getProperty("java.class.path"))) {
-                var path = Paths.get(entry);
-                if (Files.exists(path)) classpath.add(LoaderUtil.normalizeExistingPath(path));
-            }
-        }
-
-        @Override
-        public void addToClassPath(Path path, String... allowedPrefixes) {
-            classpath.add(path);
-        }
-
-        @Override
-        public void setAllowedPrefixes(Path path, String... prefixes) {
-        }
-
-        @Override
-        public void setValidParentClassPath(Collection<Path> paths) {
-            throw new UnsupportedOperationException("setValidParentClassPath");
-        }
-
-        @Override
-        public EnvType getEnvironmentType() {
-            return EnvType.CLIENT;
-        }
-
-        @Override
-        public boolean isClassLoaded(String name) {
-            return false;
-        }
-
-        @Override
-        public Class<?> loadIntoTarget(String name) {
-            throw new UnsupportedOperationException("loadIntoTarget");
-        }
-
-        @Override
-        public ClassLoader getTargetClassLoader() {
-            return Thread.currentThread().getContextClassLoader();
-        }
-
-        @Override
-        public @Nullable InputStream getResourceAsStream(String name) {
-            return BasicLauncher.class.getClassLoader().getResourceAsStream(name);
-        }
-
-        @Override
-        public @Nullable byte[] getClassByteArray(String name, boolean runTransformers) throws IOException {
-            try (var stream = BasicLauncher.class.getClassLoader().getResourceAsStream(LoaderUtil.getClassFileName(name))) {
-                if (stream == null) return null;
-                return ByteStreams.toByteArray(stream);
-            }
-        }
-
-        @Override
-        public Manifest getManifest(Path originPath) {
-            throw new UnsupportedOperationException("getManifest");
-        }
-
-        @Override
-        public boolean isDevelopment() {
-            return true;
-        }
-
-        @Override
-        public String getEntrypoint() {
-            throw new UnsupportedOperationException("getEntrypoint");
-        }
-
-        @Override
-        public String getTargetNamespace() {
-            return "named";
-        }
-
-        @Override
-        public List<Path> getClassPath() {
-            return classpath;
-        }
-    }
-
-    private static final class ClassTransformer implements ClassFileTransformer {
-        private final IMixinTransformer transformer;
-        private final Set<String> definedClasses = new HashSet<>();
-        private final Set<String> generatedClasses;
-
-        private ClassTransformer(IMixinTransformer transformer) {
-            this.transformer = transformer;
-
-            try {
-                // As we can't hook into classloading itself, we need to track all the classes Mixin has generated. Yes,
-                // this is nasty.
-                var syntheticRegistryField = transformer.getClass().getDeclaredField("syntheticClassRegistry");
-                syntheticRegistryField.setAccessible(true);
-                var syntheticRegistry = syntheticRegistryField.get(transformer);
-
-                var classesField = syntheticRegistry.getClass().getDeclaredField("classes");
-                classesField.setAccessible(true);
-                @SuppressWarnings("unchecked") var classes = (Map<String, ?>) classesField.get(syntheticRegistry);
-                generatedClasses = classes.keySet();
-            } catch (ReflectiveOperationException e) {
-                throw new RuntimeException(e);
-            }
-        }
-
-        @Override
-        public synchronized @Nullable byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] bytes) throws IllegalClassFormatException {
-            var name = className.replace('/', '.');
-            var transformed = FabricTransformer.transform(true, EnvType.CLIENT, name, bytes);
-            transformed = transformer.transformClassBytes(name, name, transformed);
-
-            // Keep track of all generated classes that we've seen, and define any new ones. We use ByteBuddy to inject
-            // the new class definitions, as doing it ourselves is hard.
-            if (generatedClasses.size() > definedClasses.size()) {
-                var toDefine = generatedClasses.stream().filter(definedClasses::add).collect(Collectors.toUnmodifiableMap(
-                    genName -> genName.replace('/', '.'),
-                    genName -> transformer.generateClass(MixinEnvironment.getDefaultEnvironment(), genName)
-                ));
-
-                LOG.info("Defining {}", toDefine.keySet());
-                try {
-                    new ClassInjector.UsingReflection(loader).injectRaw(toDefine);
-                } catch (Exception e) {
-                    LOG.error("Failed to define {}", className, e);
-                }
-            }
-
-            return transformed == bytes ? null : transformed;
-        }
-    }
-}