SPIGOT-5805: NPE when getting an Attribute from a Player

By: md_5 <git@md-5.net>

paper-server/src/test/java/org/bukkit/craftbukkit/attribute/AttributeTest.java

@@ -0,0 +1,30 @@
+package org.bukkit.craftbukkit.attribute;
+
+import net.minecraft.server.AttributeBase;
+import net.minecraft.server.IRegistry;
+import net.minecraft.server.MinecraftKey;
+import org.bukkit.attribute.Attribute;
+import org.bukkit.support.AbstractTestingBase;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class AttributeTest extends AbstractTestingBase {
+
+    @Test
+    public void testToBukkit() {
+        for (MinecraftKey nms : IRegistry.ATTRIBUTE.keySet()) {
+            Attribute bukkit = CraftAttributeMap.fromMinecraft(nms.toString());
+
+            Assert.assertNotNull(nms.toString(), bukkit);
+        }
+    }
+
+    @Test
+    public void testToNMS() {
+        for (Attribute attribute : Attribute.values()) {
+            AttributeBase nms = CraftAttributeMap.toMinecraft(attribute);
+
+            Assert.assertNotNull(attribute.name(), nms);
+        }
+    }
+}