Add regression tests for dirty region and setData edge cases

Author: riccardobl

jme3-core/src/test/java/com/jme3/shader/bufferobject/DirtyRegionsIteratorTest.java

@@ -0,0 +1,91 @@
+package com.jme3.shader.bufferobject;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+public class DirtyRegionsIteratorTest {
+
+    @Test
+    public void testNoRegionsFullUpdateRangeAndSliceLength() {
+        BufferObject bo = new BufferObject();
+        bo.initializeEmpty(8);
+        bo.setUpdateNeeded(false);
+
+        BufferRegion region = bo.getDirtyRegions().next();
+        assertNotNull(region);
+        assertTrue(region.isFullBufferRegion());
+        assertEquals(0, region.getStart());
+        assertEquals(7, region.getEnd());
+        assertEquals(8, region.getData().remaining());
+
+        region.clearDirty();
+        bo.clearUpdateNeeded();
+        assertFalse(bo.isUpdateNeeded());
+    }
+
+    @Test
+    public void testMergedDirtyRegionSliceUsesInclusiveEnd() {
+        BufferObject bo = new BufferObject();
+        bo.setRegions(Arrays.asList(
+                new BufferRegion(0, 3),
+                new BufferRegion(4, 7),
+                new BufferRegion(8, 11)));
+
+        bo.getRegion(0).markDirty();
+        bo.getRegion(1).markDirty();
+        bo.getRegion(2).clearDirty();
+
+        bo.setUpdateNeeded(false);
+
+        BufferRegion region = bo.getDirtyRegions().next();
+        assertNotNull(region);
+        assertFalse(region.isFullBufferRegion());
+        assertEquals(0, region.getStart());
+        assertEquals(7, region.getEnd());
+        assertEquals(8, region.getData().remaining());
+    }
+
+    @Test
+    public void testNoRegionsHasNextContract() {
+        BufferObject bo = new BufferObject();
+        bo.initializeEmpty(4);
+        bo.setUpdateNeeded(false);
+
+        DirtyRegionsIterator iterator = bo.getDirtyRegions();
+        assertTrue(iterator.hasNext());
+
+        BufferRegion region = iterator.next();
+        assertNotNull(region);
+        assertFalse(iterator.hasNext());
+        assertEquals(4, region.getData().remaining());
+    }
+
+    @Test
+    public void testSetDataHandlesSelfAlias() {
+        BufferObject bo = new BufferObject();
+        ByteBuffer source = ByteBuffer.allocateDirect(4);
+        source.put((byte) 0x11);
+        source.put((byte) 0x22);
+        source.put((byte) 0x33);
+        source.put((byte) 0x44);
+        source.flip();
+        bo.setData(source);
+
+        ByteBuffer sameBuffer = bo.getData();
+        bo.setData(sameBuffer);
+
+        ByteBuffer result = bo.getData();
+        assertEquals(4, result.remaining());
+        assertEquals((byte) 0x11, result.get());
+        assertEquals((byte) 0x22, result.get());
+        assertEquals((byte) 0x33, result.get());
+        assertEquals((byte) 0x44, result.get());
+    }
+}