feat: add flush events action when app move to background. (#21)

Co-authored-by: xiaoweii <xiaoweii@amazom.com>

Author: zhu-xiaowei

clickstream/src/main/java/software/aws/solution/clickstream/client/AutoRecordEventClient.java

@@ -110,6 +110,7 @@ public void recordUserEngagement() {
             event.addAttribute(Event.ReservedAttribute.SCREEN_ID, ScreenRefererTool.getCurrentScreenId());
             this.clickstreamContext.getAnalyticsClient().recordEvent(event);
         }
+        this.clickstreamContext.getAnalyticsClient().submitEvents();
     }
 
     /**

clickstream/src/test/java/software/aws/solution/clickstream/AutoRecordEventClientTest.java

@@ -39,13 +39,16 @@
 import software.aws.solution.clickstream.client.ClickstreamContext;
 import software.aws.solution.clickstream.client.ClickstreamManager;
 import software.aws.solution.clickstream.client.Event;
+import software.aws.solution.clickstream.client.EventRecorder;
 import software.aws.solution.clickstream.client.ScreenRefererTool;
 import software.aws.solution.clickstream.client.db.ClickstreamDBUtil;
 import software.aws.solution.clickstream.client.util.StringUtil;
 import software.aws.solution.clickstream.util.ReflectUtil;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.ThreadPoolExecutor;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
@@ -411,6 +414,23 @@ public void testHandleAppStart() throws Exception {
         }
     }
 
+    /**
+     * test case for app move to background with flush event.
+     *
+     * @throws Exception exception.
+     */
+    @Test
+    public void testBackgroundRequest() throws Exception {
+        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_START);
+        Thread.sleep(1100);
+        lifecycle.handleLifecycleEvent(Lifecycle.Event.ON_STOP);
+        EventRecorder eventRecorder =
+            (EventRecorder) ReflectUtil.getFiled(clickstreamContext.getAnalyticsClient(), "eventRecorder");
+        ExecutorService executorService =
+            (ExecutorService) ReflectUtil.getFiled(eventRecorder, "submissionRunnableQueue");
+        assertEquals(1, ((ThreadPoolExecutor) executorService).getActiveCount());
+    }
+
     /**
      * test init autoRecordEventClient with null analyticsClient.
      */