Fix intermittent failure in Balking pattern describe in iluwatar#699

Author: staillebois

balking/src/test/java/com/iluwatar/balking/WashingMachineTest.java

@@ -22,31 +22,36 @@
  */
 package com.iluwatar.balking;
 
-import org.junit.jupiter.api.Disabled;
-import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 
-import static org.junit.jupiter.api.Assertions.assertEquals;
+import org.junit.jupiter.api.Test;
 
 /**
  * Tests for {@link WashingMachine}
  */
 public class WashingMachineTest {
 
-  private volatile WashingMachineState machineStateGlobal;
+  private WashingMachineState machineStateGlobal;
 
-  @Disabled
   @Test
   public void wash() throws Exception {
     WashingMachine washingMachine = new WashingMachine();
     ExecutorService executorService = Executors.newFixedThreadPool(2);
-    executorService.execute(washingMachine::wash);
     executorService.execute(() -> {
       washingMachine.wash();
-      machineStateGlobal = washingMachine.getWashingMachineState();
+      if(machineStateGlobal==null) {
+        machineStateGlobal = washingMachine.getWashingMachineState();
+      }
+    });
+    executorService.execute(() -> {
+      washingMachine.wash();
+      if(machineStateGlobal==null) {
+        machineStateGlobal = washingMachine.getWashingMachineState();
+      }
     });
     executorService.shutdown();
     try {