add test class

src/test/java/com/fasterxml/jackson/core/write/BufferRecyclerPoolTest.java

@@ -0,0 +1,64 @@
+package com.fasterxml.jackson.core.write;
+
+import com.fasterxml.jackson.core.BaseTest;
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.util.BufferRecyclerPool;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+public class BufferRecyclerPoolTest extends BaseTest {
+
+    public void testNoOp() {
+        checkBufferRecyclerPoolImpl(BufferRecyclerPool.PoolStrategy.NO_OP);
+    }
+
+    public void testThreadLocal() {
+        checkBufferRecyclerPoolImpl(BufferRecyclerPool.PoolStrategy.THREAD_LOCAL);
+    }
+
+    public void testLockFree() {
+        checkBufferRecyclerPoolImpl(BufferRecyclerPool.PoolStrategy.LOCK_FREE);
+    }
+
+    public void testConcurrentDequeue() {
+        checkBufferRecyclerPoolImpl(BufferRecyclerPool.PoolStrategy.CONCURRENT_DEQUEUE);
+    }
+
+    private void checkBufferRecyclerPoolImpl(BufferRecyclerPool.PoolStrategy poolStrategy) {
+        JsonFactory jsonFactory = new JsonFactory().setBufferRecyclerPool(poolStrategy.getPool());
+        assertEquals(6, write("test", jsonFactory));
+    }
+
+    protected final int write(Object value, JsonFactory jsonFactory) {
+        NopOutputStream out = new NopOutputStream();
+        try (JsonGenerator gen = jsonFactory.createGenerator(out)) {
+            gen.writeObject(value);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+        return out.size();
+    }
+
+    public class NopOutputStream extends OutputStream {
+        protected int size = 0;
+
+        public NopOutputStream() { }
+
+        @Override
+        public void write(int b) throws IOException { ++size; }
+
+        @Override
+        public void write(byte[] b) throws IOException { size += b.length; }
+
+        @Override
+        public void write(byte[] b, int offset, int len) throws IOException { size += len; }
+
+        public NopOutputStream reset() {
+            size = 0;
+            return this;
+        }
+        public int size() { return size; }
+    }
+}