Officially propagate GPL downwards to all files

(cherry picked from commit f2ce020da059718e34342c149172944dfd02b775)

worldedit-core/src/test/java/com/sk89q/worldedit/internal/util/DeprecationUtilTest.java

@@ -0,0 +1,88 @@
+/*
+ * WorldEdit, a Minecraft world manipulation toolkit
+ * Copyright (C) sk89q <http://www.sk89q.com>
+ * Copyright (C) WorldEdit team and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.sk89q.worldedit.internal.util;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class DeprecationUtilTest {
+
+    public interface ModifiedApi {
+        @Deprecated
+        default boolean oldApi() {
+            return newApi();
+        }
+
+        @NonAbstractForCompatibility(
+            delegateName = "oldApi",
+            delegateParams = {}
+        )
+        default boolean newApi() {
+            DeprecationUtil.checkDelegatingOverride(getClass());
+            return oldApi();
+        }
+    }
+
+    public static class OldImpl implements ModifiedApi {
+        @SuppressWarnings("deprecation")
+        @Override
+        public boolean oldApi() {
+            return false;
+        }
+    }
+
+    public static class NewImpl implements ModifiedApi {
+        @Override
+        public boolean newApi() {
+            return true;
+        }
+    }
+
+    public static class NewBadImpl implements ModifiedApi {
+    }
+
+    @Test
+    void oldImpl() {
+        assertFalse(new OldImpl().oldApi());
+        assertFalse(new OldImpl().newApi());
+    }
+
+    @Test
+    void newImpl() {
+        assertTrue(new NewImpl().oldApi());
+        assertTrue(new NewImpl().newApi());
+    }
+
+    @Test
+    void newBadImpl() {
+        // regardless of which method is called, the message is the same
+        Exception ex = assertThrows(IllegalStateException.class, new NewBadImpl()::oldApi);
+        assertTrue(ex.getMessage().contains("must override"));
+        assertTrue(ex.getMessage().contains("ModifiedApi.newApi()"));
+
+        ex = assertThrows(IllegalStateException.class, new NewBadImpl()::newApi);
+        assertTrue(ex.getMessage().contains("must override"));
+        assertTrue(ex.getMessage().contains("ModifiedApi.newApi()"));
+    }
+
+}