Add unit tests for StreamsUtil fixes #699

Add unit tests for StreamsUtil fixes #699

src/test/java/net/openhft/chronicle/wire/internal/stream/StreamsUtilTest.java

@@ -0,0 +1,112 @@
+package net.openhft.chronicle.wire.internal.stream;
+
+import net.openhft.chronicle.core.internal.util.RangeUtil;
+import net.openhft.chronicle.core.values.DoubleValue;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.*;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Consumer;
+import java.util.function.DoubleConsumer;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+
+import static org.junit.Assert.*;
+
+public class StreamsUtilTest {
+
+    @Test
+    public void VanillaSpliterator_estimateSize_alwaysReturnsLongMaxValue() {
+        Collection<Integer> collection = Collections.emptyList();
+        StreamsUtil.VanillaSpliterator<Integer> spliterator = new StreamsUtil.VanillaSpliterator<>(collection.iterator());
+        assertEquals(Long.MAX_VALUE, spliterator.estimateSize());
+    }
+
+    @Test
+    public void VanillaSpliterator_trySplit_iteratorWithNoContentsShouldYieldNullSpliterator() {
+        Collection<Integer> collection = Collections.emptyList();
+        StreamsUtil.VanillaSpliterator<Integer> spliterator = new StreamsUtil.VanillaSpliterator<>(collection.iterator());
+        Spliterator<Integer> split = spliterator.trySplit();
+        assertNull(split);
+    }
+
+    @Test
+    public void VanillaSpliterator_trySplit_batchSizeShouldBeCappedByTwoTimesBatchUnitIncrease() {
+        Collection<Integer> collection = Stream.generate(() -> 1).limit(16777216).collect(Collectors.toList());
+        StreamsUtil.VanillaSpliterator<Integer> spliterator = new StreamsUtil.VanillaSpliterator<>(collection.iterator());
+        Spliterator<Integer> split = spliterator.trySplit();
+        assertEquals(2 * 1024, split.getExactSizeIfKnown());
+    }
+
+    @Test
+    public void VanillaSpliterator_trySplit_batchSizeSmallerThanMatchMaxSizeShouldBeReleased() {
+        Collection<Integer> collection = Stream.generate(() -> 1).limit(10).collect(Collectors.toList());
+        StreamsUtil.VanillaSpliterator<Integer> spliterator = new StreamsUtil.VanillaSpliterator<>(collection.iterator());
+        Spliterator<Integer> split = spliterator.trySplit();
+        assertEquals(10, split.getExactSizeIfKnown());
+    }
+
+    @Test
+    public void VanillaSpliteratorOfLong_split() {
+        PrimitiveIterator.OfLong iterator = LongStream.of(1, 2).iterator();
+        StreamsUtil.VanillaSpliteratorOfLong spliterator = new StreamsUtil.VanillaSpliteratorOfLong(iterator);
+        assertEquals(1, spliterator.split(1).getExactSizeIfKnown());
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_split() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.of(1, 2).iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+        assertEquals(1, spliterator.split(1).getExactSizeIfKnown());
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_trySplit_iteratorWithNoContentsShouldYieldNullSpliterator() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.empty().iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+        Spliterator.OfDouble split = spliterator.trySplit();
+        assertNull(split);
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_trySplit_batchSizeShouldBeCappedByTwoTimesBatchUnitIncrease() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.generate(() -> 1).limit(16777216).iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+        Spliterator.OfDouble split = spliterator.trySplit();
+        assertEquals(2 * 1024, split.getExactSizeIfKnown());
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_tryAdvance_nextValueShouldBeYielded() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.generate(() -> 1).limit(16777216).iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+
+        AtomicReference<Double> doubleReference = new AtomicReference<>();
+        boolean result = spliterator.tryAdvance((DoubleConsumer) doubleReference::set);
+        assertEquals(1d, doubleReference.get(), 0);
+        assertTrue(result);
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_tryAdvance_noValueYieldedForEmptyStream() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.empty().iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+
+        AtomicReference<Double> doubleReference = new AtomicReference<>();
+        boolean result = spliterator.tryAdvance((DoubleConsumer) doubleReference::set);
+        assertNull(doubleReference.get());
+        assertFalse(result);
+    }
+
+    @Test
+    public void VanillaSpliteratorOfDouble_estimateSize_alwaysReturnsLongMaxValue() {
+        PrimitiveIterator.OfDouble iterator = DoubleStream.empty().iterator();
+        StreamsUtil.VanillaSpliteratorOfDouble spliterator = new StreamsUtil.VanillaSpliteratorOfDouble(iterator);
+        assertEquals(Long.MAX_VALUE, spliterator.estimateSize());
+    }
+
+}