Added tests for thread-pool pattern

Fixed concurrency problem in id generation of Task

thread-pool/src/test/java/com/iluwatar/threadpool/CoffeeMakingTaskTest.java

@@ -0,0 +1,17 @@
+package com.iluwatar.threadpool;
+
+/**
+ * Date: 12/30/15 - 18:23 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class CoffeeMakingTaskTest extends TaskTest<CoffeeMakingTask> {
+
+  /**
+   * Create a new test instance
+   */
+  public CoffeeMakingTaskTest() {
+    super(CoffeeMakingTask::new, 100);
+  }
+
+}