Add unit tests CircularLongBuffer (#960)

src/test/java/com/uber/cadence/internal/worker/CircularLongBufferTest.java

@@ -0,0 +1,54 @@
+/**
+ * Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * <p>Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ * <p>Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file
+ * except in compliance with the License. A copy of the License is located at
+ *
+ * <p>http://aws.amazon.com/apache2.0
+ *
+ * <p>or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ */
+package com.uber.cadence.internal.worker;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThrows;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CircularLongBufferTest {
+
+  private CircularLongBuffer buffer;
+  private CircularLongBuffer buffer2;
+
+  @Before
+  public void setUp() {
+    // Initialize a buffer with specific values for testing
+    buffer = new CircularLongBuffer(new long[] {1, 2, 3, 4, 5});
+    buffer2 = new CircularLongBuffer(new long[] {});
+  }
+
+  @Test
+  public void testCopyZeroLength() {
+    // Copy with zero length should result in an empty buffer
+    CircularLongBuffer copyBuffer = buffer.copy(2, 0);
+    assertEquals(0, copyBuffer.size());
+  }
+
+  @Test
+  public void testEdgeCase() {
+    // Copy with zero length should result in an empty buffer
+    CircularLongBuffer copyBuffer = buffer.copy(100, 3);
+    assertEquals(3, copyBuffer.size());
+  }
+
+  @Test
+  public void testValuesZero() {
+    // Copy with zero length should result in an empty buffer
+    assertThrows(IllegalStateException.class, () -> buffer2.copy(2, 3));
+  }
+}