Add SpinLock test

src/test/java/org/wildfly/common/lock/SpinLockTest.java

@@ -0,0 +1,70 @@
+package org.wildfly.common.lock;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.LockSupport;
+
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ *
+ */
+public class SpinLockTest {
+
+    static final int POOL_SIZE = 16;
+    static final int SPIN_COUNT = 20480;
+
+    static ThreadPoolExecutor executor;
+
+    @BeforeClass
+    public static void initialize() {
+        executor = new ThreadPoolExecutor(POOL_SIZE, POOL_SIZE, Long.MAX_VALUE, TimeUnit.DAYS, new LinkedBlockingQueue<>());
+        executor.prestartAllCoreThreads();
+    }
+
+    @Test
+    public void ensureLockWorks() {
+        SpinLock lock = new SpinLock();
+        int[] holder = new int[1];
+        CountDownLatch latch = new CountDownLatch(POOL_SIZE);
+        for (int i = 0; i < POOL_SIZE; i ++) {
+            executor.execute(() -> {
+                LockSupport.parkNanos(100_000L);
+                for (int j = 0; j < SPIN_COUNT; j ++) {
+                    lock.lock();
+                    try {
+                        holder[0] ++;
+                    } finally {
+                        lock.unlock();
+                    }
+                }
+                latch.countDown();
+            });
+        }
+        for (;;) try {
+            latch.await();
+            break;
+        } catch (InterruptedException ignored) {
+        }
+        Assert.assertEquals("Wrong final count", POOL_SIZE * SPIN_COUNT, holder[0]);
+    }
+
+
+    @AfterClass
+    public static void shutdown() {
+        ThreadPoolExecutor executor = SpinLockTest.executor;
+        if (executor != null) {
+            executor.shutdownNow();
+            for (;;) try {
+                executor.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
+                break;
+            } catch (InterruptedException ignored) {
+            }
+        }
+    }
+}