[RIP-10] Add test cases for CountDownLatch2 (#868)

common/src/test/java/org/apache/rocketmq/common/CountDownLatch2Test.java

+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License 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 org.apache.rocketmq.common;
+
+import org.junit.Test;
+
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.core.Is.is;
+import static org.hamcrest.core.StringContains.containsString;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * CountDownLatch2 Unit Test
+ *
+ * @see CountDownLatch2
+ */
+public class CountDownLatch2Test {
+
+    /**
+     * test constructor with invalid init param
+     *
+     * @see CountDownLatch2#CountDownLatch2(int)
+     */
+    @Test
+    public void testConstructorError() {
+        int count = -1;
+        try {
+            CountDownLatch2 latch = new CountDownLatch2(count);
+        } catch (IllegalArgumentException e) {
+            assertThat(e.getMessage(), is("count < 0"));
+        }
+    }
+
+    /**
+     * test constructor with valid init param
+     *
+     * @see CountDownLatch2#CountDownLatch2(int)
+     */
+    @Test
+    public void testConstructor() {
+        int count = 10;
+        CountDownLatch2 latch = new CountDownLatch2(count);
+        assertEquals("Expected equal", count, latch.getCount());
+        assertThat("Expected contain", latch.toString(), containsString("[Count = " + count + "]"));
+    }
+
+    /**
+     * test await timeout
+     *
+     * @see CountDownLatch2#await(long, TimeUnit)
+     */
+    @Test
+    public void testAwaitTimeout() throws InterruptedException {
+        int count = 1;
+        CountDownLatch2 latch = new CountDownLatch2(count);
+        boolean await = latch.await(10, TimeUnit.MILLISECONDS);
+        assertFalse("Expected false", await);
+
+        latch.countDown();
+        boolean await2 = latch.await(10, TimeUnit.MILLISECONDS);
+        assertTrue("Expected true", await2);
+    }
+
+
+    /**
+     * test reset
+     *
+     * @see CountDownLatch2#countDown()
+     */
+    @Test(timeout = 1000)
+    public void testCountDownAndGetCount() throws InterruptedException {
+        int count = 2;
+        CountDownLatch2 latch = new CountDownLatch2(count);
+        assertEquals("Expected equal", count, latch.getCount());
+        latch.countDown();
+        assertEquals("Expected equal", count - 1, latch.getCount());
+        latch.countDown();
+        latch.await();
+        assertEquals("Expected equal", 0, latch.getCount());
+    }
+
+
+    /**
+     * test reset
+     *
+     * @see CountDownLatch2#reset()
+     */
+    @Test
+    public void testReset() throws InterruptedException {
+        int count = 2;
+        CountDownLatch2 latch = new CountDownLatch2(count);
+        latch.countDown();
+        assertEquals("Expected equal", count - 1, latch.getCount());
+        latch.reset();
+        assertEquals("Expected equal", count, latch.getCount());
+        latch.countDown();
+        latch.countDown();
+        latch.await();
+        assertEquals("Expected equal", 0, latch.getCount());
+        // coverage Sync#tryReleaseShared, c==0
+        latch.countDown();
+        assertEquals("Expected equal", 0, latch.getCount());
+    }
+}