Fix lighting tests & heightmap (#137)

* fix tests

* fix heightmap lookup

(cherry picked from commit 7d717ada584bc3a3feaeda470113bb4adeb774ae)

src/main/java/net/minestom/server/instance/LightingChunk.java

@@ -342,6 +342,8 @@ public class LightingChunk extends DynamicChunk {
                 if (chunkCheck == null) continue;
 
                 if (chunkCheck instanceof LightingChunk lighting) {
+                    // Ensure heightmap is calculated before taking values from it
+                    lighting.getHeightmap();
                     if (lighting.highestBlock > highestRegionPoint) highestRegionPoint = lighting.highestBlock;
                 }
             }

src/test/java/net/minestom/server/instance/BlockLightMergeIntegrationTest.java

@@ -139,7 +139,7 @@ public class BlockLightMergeIntegrationTest {
             expectedLights.put(new Vec(-2, 100 + y, 8), 0);
         }
 
-        LightingChunk.relightSection(instance, 0, 2, 0);
+        LightingChunk.relightSection(instance, 0, 6, 0);
 
         assertLightInstance(instance, expectedLights);
     }

src/test/java/net/minestom/server/instance/light/WorldRelightIntegrationTest.java

@@ -30,6 +30,7 @@ public class WorldRelightIntegrationTest {
     @Test
     public void testBorderLava(Env env) {
         Instance instance = env.createFlatInstance();
+        instance.setChunkSupplier(LightingChunk::new);
         instance.loadChunk(6, 16).join();
         instance.loadChunk(6, 15).join();
 
@@ -47,6 +48,7 @@ public class WorldRelightIntegrationTest {
     @Test
     public void testBlockRemoval(Env env) {
         Instance instance = createLightingInstance(env.process());
+        instance.setChunkSupplier(LightingChunk::new);
         for (int x = -3; x <= 3; x++) {
             for (int z = -3; z <= 3; z++) {
                 instance.loadChunk(x, z).join();