Add fabric-loader-junit to allow unit testing of transformed classes.

.gitignore

@@ -21,4 +21,5 @@
 !/settings.gradle
 !/proguard.conf
 
-!/minecraft
+!/minecraft
+!/junit

build.gradle

@@ -12,7 +12,7 @@ plugins {
 	id 'maven-publish'
 	id 'checkstyle'
 	id 'com.diffplug.spotless' version "6.12.0"
-	id 'fabric-loom' version '1.0-SNAPSHOT' apply false
+	id 'fabric-loom' version '1.1-SNAPSHOT' apply false
 	id 'com.github.johnrengelman.shadow' version '7.1.2'
 	id 'me.modmuss50.remotesign' version "0.4.0"
 }
@@ -84,7 +84,7 @@ dependencies {
 	testCompileOnly 'org.jetbrains:annotations:23.0.0'
 
 	// Unit testing for mod metadata
-	testImplementation('org.junit.jupiter:junit-jupiter:5.8.2')
+	testImplementation('org.junit.jupiter:junit-jupiter:5.9.2')
 }
 
 processResources {

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.0.1-bin.zip
 networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -144,15 +144,15 @@ if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
         # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045 
+        # shellcheck disable=SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
         # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045 
+        # shellcheck disable=SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac

junit/.gitignore

@@ -0,0 +1,6 @@
+# Ignore everything
+/*
+
+!/src
+!/build.gradle
+!/.gitignore

junit/build.gradle

@@ -0,0 +1,61 @@
+apply plugin: 'maven-publish'
+apply plugin: 'me.modmuss50.remotesign'
+
+sourceCompatibility = JavaVersion.VERSION_1_8
+targetCompatibility = JavaVersion.VERSION_1_8
+
+archivesBaseName = "fabric-loader-junit"
+version = rootProject.version
+group = rootProject.group
+
+def ENV = System.getenv()
+def signingEnabled = ENV.SIGNING_SERVER
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	api project(":")
+
+	api platform("org.junit:junit-bom:5.9.2")
+	api "org.junit.jupiter:junit-jupiter-engine"
+	implementation "org.junit.platform:junit-platform-launcher"
+}
+
+java {
+	withSourcesJar()
+}
+
+if (signingEnabled) {
+	remoteSign {
+		requestUrl = ENV.SIGNING_SERVER
+		pgpAuthKey = ENV.SIGNING_PGP_KEY
+		jarAuthKey = ENV.SIGNING_JAR_KEY
+
+		afterEvaluate {
+			sign publishing.publications.maven
+		}
+	}
+}
+
+publishing {
+	publications {
+		mavenJava(MavenPublication) {
+			artifactId project.archivesBaseName
+			from components.java
+		}
+	}
+
+	repositories {
+		if (ENV.MAVEN_URL) {
+			maven {
+				url ENV.MAVEN_URL
+				credentials {
+					username ENV.MAVEN_USERNAME
+					password ENV.MAVEN_PASSWORD
+				}
+			}
+		}
+	}
+}

junit/src/main/java/net/fabricmc/loader/impl/junit/FabricLoaderLauncherSessionListener.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2016 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.loader.impl.junit;
+
+import org.junit.platform.launcher.LauncherSession;
+import org.junit.platform.launcher.LauncherSessionListener;
+
+import net.fabricmc.api.EnvType;
+import net.fabricmc.loader.impl.launch.knot.Knot;
+import net.fabricmc.loader.impl.util.SystemProperties;
+
+public class FabricLoaderLauncherSessionListener implements LauncherSessionListener {
+	static {
+		System.setProperty(SystemProperties.DEVELOPMENT, "true");
+		System.setProperty(SystemProperties.UNIT_TEST, "true");
+	}
+
+	private final Knot knot;
+	private final ClassLoader classLoader;
+
+	private ClassLoader launcherSessionClassLoader;
+
+	public FabricLoaderLauncherSessionListener() {
+		final Thread currentThread = Thread.currentThread();
+		final ClassLoader originalClassLoader = currentThread.getContextClassLoader();
+
+		try {
+			knot = new Knot(EnvType.CLIENT);
+			classLoader = knot.init(new String[]{});
+		} finally {
+			// Knot.init sets the context class loader, revert it back for now.
+			currentThread.setContextClassLoader(originalClassLoader);
+		}
+	}
+
+	@Override
+	public void launcherSessionOpened(LauncherSession session) {
+		final Thread currentThread = Thread.currentThread();
+		launcherSessionClassLoader = currentThread.getContextClassLoader();
+		currentThread.setContextClassLoader(classLoader);
+	}
+
+	@Override
+	public void launcherSessionClosed(LauncherSession session) {
+		final Thread currentThread = Thread.currentThread();
+		currentThread.setContextClassLoader(launcherSessionClassLoader);
+	}
+}

junit/src/main/resources/META-INF/services/org.junit.platform.launcher.LauncherSessionListener

@@ -0,0 +1 @@
+net.fabricmc.loader.impl.junit.FabricLoaderLauncherSessionListener

minecraft/minecraft-test/build.gradle

@@ -11,11 +11,17 @@ loom {
 
 def minecraft_version = "1.19.3";
 
+repositories {
+	mavenCentral()
+}
+
 dependencies {
 	minecraft "com.mojang:minecraft:${minecraft_version}"
 	mappings "net.fabricmc:yarn:${minecraft_version}+build.3:v2"
 
 	implementation project(":minecraft")
+	implementation project(":minecraft").sourceSets.main.output
+	implementation project(":").sourceSets.main.output
 
 	// Required for mixin annotation processor
 	annotationProcessor "org.ow2.asm:asm:${project.asm_version}"
@@ -32,6 +38,12 @@ dependencies {
 		exclude module: 'launchwrapper'
 		exclude module: 'guava'
 	}
+
+	testImplementation project(":junit")
+}
+
+test {
+	useJUnitPlatform()
 }
 
 tasks.withType(JavaCompile).configureEach {

minecraft/minecraft-test/src/main/java/net/fabricmc/minecraft/test/mixin/MixinGuiMain.java → minecraft/minecraft-test/src/main/java/net/fabricmc/minecraft/test/mixin/MixinGrassBlock.java

@@ -19,21 +19,18 @@
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Inject;
-import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 
-import net.minecraft.client.gui.screen.Screen;
-import net.minecraft.client.gui.screen.TitleScreen;
-import net.minecraft.client.util.math.MatrixStack;
-import net.minecraft.text.Text;
+import net.minecraft.block.BlockState;
+import net.minecraft.block.GrassBlock;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.random.Random;
+import net.minecraft.world.World;
 
-@Mixin(value = TitleScreen.class, remap = false)
-public abstract class MixinGuiMain extends Screen {
-	protected MixinGuiMain(Text textComponent_1) {
-		super(textComponent_1);
-	}
-
-	@Inject(method = "render", at = @At("RETURN"))
-	public void render(MatrixStack matrixStack, int mouseX, int mouseY, float delta, CallbackInfo info) {
-		this.textRenderer.draw(matrixStack, "Fabric Test Mod", 2, this.height - 30, -1);
+@Mixin(GrassBlock.class)
+public class MixinGrassBlock {
+	@Inject(method = "canGrow", at = @At("HEAD"), cancellable = true)
+	public void canGrow(World world, Random random, BlockPos pos, BlockState state, CallbackInfoReturnable<Boolean> cir) {
+		cir.setReturnValue(false);
 	}
 }

minecraft/minecraft-test/src/main/resources/fabricmc.test.mixins.client.json

@@ -3,6 +3,7 @@
     "package": "net.fabricmc.minecraft.test.mixin",
     "compatibilityLevel": "JAVA_8",
     "mixins": [
+      "MixinGrassBlock"
     ],
     "injectors": {
         "defaultRequire": 1

minecraft/minecraft-test/src/test/java/net/fabricmc/minecraft/test/junit/JunitTest.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2016 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.minecraft.test.junit;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import net.minecraft.Bootstrap;
+import net.minecraft.SharedConstants;
+import net.minecraft.block.Blocks;
+import net.minecraft.block.GrassBlock;
+import net.minecraft.item.Items;
+import net.minecraft.registry.Registries;
+import net.minecraft.util.Identifier;
+
+import net.fabricmc.loader.api.FabricLoader;
+
+public class JunitTest {
+	@BeforeAll
+	public static void setup() {
+		SharedConstants.createGameVersion();
+		Bootstrap.initialize();
+	}
+
+	@Test
+	public void testItems() {
+		Identifier id = Registries.ITEM.getId(Items.DIAMOND);
+		assertEquals(id.toString(), "minecraft:diamond");
+
+		System.out.println(id);
+	}
+
+	@Test
+	public void testMixin() {
+		// MixinGrassBlock sets canGrow to false
+		GrassBlock grassBlock = (GrassBlock) Blocks.GRASS_BLOCK;
+		boolean canGrow = grassBlock.canGrow(null, null, null, null);
+		assertFalse(canGrow);
+	}
+
+	@Test
+	public void testAccessLoader() {
+		FabricLoader.getInstance().getAllMods();
+	}
+}

minecraft/src/main/java/net/fabricmc/loader/impl/game/minecraft/MinecraftGameProvider.java

@@ -325,7 +325,8 @@ public void initialize(FabricLauncher launcher) {
 			realmsJar = obfJars.get("realms");
 		}
 
-		if (!logJars.isEmpty()) {
+		// Load the logger libraries on the platform CL when in a unit test
+		if (!logJars.isEmpty() && !Boolean.getBoolean(SystemProperties.UNIT_TEST)) {
 			for (Path jar : logJars) {
 				if (gameJars.contains(jar)) {
 					launcher.addToClassPath(jar, ALLOWED_EARLY_CLASS_PREFIXES);

settings.gradle

@@ -10,6 +10,7 @@ pluginManagement {
 rootProject.name='fabric-loader'
 
 include "minecraft"
+include "junit"
 
 if (JavaVersion.current().isCompatibleWith(JavaVersion.VERSION_17)) {
 	include "minecraft:minecraft-test"