Add drops to shear events

paper-server/src/test/java/io/papermc/paper/entity/ShearableDropsTest.java

@@ -0,0 +1,35 @@
+package io.papermc.paper.entity;
+
+import io.github.classgraph.ClassGraph;
+import io.github.classgraph.ClassInfo;
+import io.github.classgraph.MethodInfoList;
+import io.github.classgraph.ScanResult;
+import java.util.ArrayList;
+import net.minecraft.world.entity.Shearable;
+import org.bukkit.support.environment.Normal;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+@Normal
+class ShearableDropsTest {
+
+    static Iterable<ClassInfo> parameters() {
+        try (ScanResult scanResult = new ClassGraph()
+            .enableClassInfo()
+            .enableMethodInfo()
+            .whitelistPackages("net.minecraft")
+            .scan()
+        ) {
+            return new ArrayList<>(scanResult.getClassesImplementing(Shearable.class.getName()));
+        }
+    }
+
+    @ParameterizedTest
+    @MethodSource("parameters")
+    void checkShearableDropOverrides(final ClassInfo classInfo) {
+        final MethodInfoList generateDefaultDrops = classInfo.getDeclaredMethodInfo("generateDefaultDrops");
+        assertEquals(1, generateDefaultDrops.size(), classInfo.getName() + " doesn't implement Shearable#generateDefaultDrops");
+    }
+}