[Bleeding] Added Potions API. Fixes BUKKIT-389

By: fullwall <fullwall@optusnet.com>

paper-server/src/test/java/org/bukkit/potion/PotionTest.java

@@ -0,0 +1,27 @@
+package org.bukkit.potion;
+
+import static org.junit.Assert.*;
+
+import org.bukkit.craftbukkit.potion.CraftPotionBrewer;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import net.minecraft.server.MobEffectList;
+
+public class PotionTest {
+    @BeforeClass
+    public static void setUp() {
+        Potion.setPotionBrewer(new CraftPotionBrewer());
+        MobEffectList.BLINDNESS.getClass();
+        PotionEffectType.stopAcceptingRegistrations();
+    }
+
+    @Test
+    public void getEffects() {
+        for (PotionType type : PotionType.values()) {
+            for (PotionEffect effect : new Potion(type).getEffects()) {
+                assertTrue(effect.getType() == PotionEffectType.getById(effect.getType().getId()));
+            }
+        }
+    }
+}