Improve testing mode.

Author: Fox2Code

loader/src/main/java/com/fox2code/foxloader/internal/InternalLoggingHooks.java

@@ -47,6 +47,7 @@ public static void setupLogAgentFoxLoader(LogAgent logAgent) {
         Logger logger = logAgent.getLogger();
         logger.setUseParentHandlers(false);
         logger.addHandler(CONSOLE_HANDLER);
+        if (FoxLauncher.isTestingMode()) return;
         FoxLauncher.installLoggerHelperOn(logger);
         if (logAgent.logFile == null || !restoreVanillaLogging) return;
         try {

loader/src/main/java/com/fox2code/foxloader/launcher/FoxLauncher.java

@@ -24,6 +24,7 @@
 package com.fox2code.foxloader.launcher;
 
 import com.fox2code.foxloader.dependencies.DependencyHelper;
+import com.fox2code.foxloader.loader.early.EarlyLoader;
 import com.fox2code.foxloader.utils.Platform;
 import com.fox2code.foxloader.utils.SourceUtil;
 import com.fox2code.foxloader.utils.io.CertificateHelper;
@@ -364,7 +365,11 @@ public static void printEarlyStackTrace(Throwable t) {
 
     public static void notifyTestingMode() {
         if (foxClassLoader == null && environmentType == null) {
-            testingMode = true;
+            // We usually can't call loader classes from launch, but testing mode is an exception.
+            if (!testingMode) {
+                testingMode = true;
+                EarlyLoader.onTestingMode();
+            }
         } else {
             throw new IllegalStateException("Cannot notify testing mode outside of unit tests!");
         }

loader/src/main/java/com/fox2code/foxloader/loader/early/EarlyLoader.java

@@ -42,4 +42,9 @@ public static void earlyLoad() {
             CoreConstants.CORE = new MinecraftServer();
         }
     }
+
+    public static void onTestingMode() {
+        if (CoreConstants.CORE != null) return;
+        CoreConstants.CORE = new Testing();
+    }
 }

loader/src/main/java/com/fox2code/foxloader/loader/early/Testing.java

@@ -0,0 +1,61 @@
+/*
+ * MIT License
+ * 
+ * Copyright (c) 2023-2025 Fox2Code
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.fox2code.foxloader.loader.early;
+
+import net.minecraft.common.ICoreAccess;
+import net.minecraft.common.entity.Entity;
+import net.minecraft.common.entity.player.PlayerInteractionHandler;
+import net.minecraft.common.util.logging.LogAgent;
+
+import java.io.File;
+import java.util.List;
+
+final class Testing implements ICoreAccess {
+    static final LogAgent TESTING_LOG_AGENT = new LogAgent("TESTING", null);
+
+    @Override
+    public File getMinecraftDir() {
+        throw new IllegalStateException("getMinecraftDir() is not available in testing mode");
+    }
+
+    @Override
+    public PlayerInteractionHandler getPlayerInteractionHandler() {
+        throw new IllegalStateException("getPlayerInteractionHandler() is not available in testing mode");
+    }
+
+    @Override
+    public void tickSprint(int i) {
+        throw new IllegalStateException("tickSprint() is not available in testing mode");
+    }
+
+    @Override
+    public LogAgent getLogger() {
+        return TESTING_LOG_AGENT;
+    }
+
+    @Override
+    public void appendAllLoadedEntities(List<Entity> list) {
+        throw new IllegalStateException("appendAllLoadedEntities() is not available in testing mode");
+    }
+}