Add request timer tests (#431)

Author: hborisoff

AndroidSDKCore/src/main/java/com/leanplum/internal/RequestSenderTimer.java

@@ -21,6 +21,7 @@
 package com.leanplum.internal;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
 import com.leanplum.EventsUploadInterval;
 import com.leanplum.internal.Request.RequestType;
 
@@ -34,7 +35,8 @@ public static RequestSenderTimer get() {
     return INSTANCE;
   }
 
-  private long getIntervalMillis() {
+  @VisibleForTesting
+  protected long getIntervalMillis() {
     return timerInterval.getMinutes() * 60 * 1000;
   }
 
@@ -46,7 +48,8 @@ private void sendAllRequestsWithHeartbeat() {
     RequestSender.getInstance().send(request);
   }
 
-  private Runnable createTimerOperation() {
+  @VisibleForTesting
+  protected Runnable createTimerOperation() {
     return new Runnable() {
       @Override
       public void run() {

AndroidSDKTests/src/test/java/com/leanplum/internal/RequestSenderTimerTest.java

@@ -0,0 +1,52 @@
+package com.leanplum.internal;
+
+import com.leanplum.EventsUploadInterval;
+import static org.junit.Assert.*;
+
+import com.leanplum.__setup.AbstractTest;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+public class RequestSenderTimerTest extends AbstractTest {
+
+  private boolean operationExecuted;
+
+  @Test
+  public void testDefaultInterval() {
+    RequestSenderTimer timer = new RequestSenderTimer();
+    assertEquals(15*60*1000, timer.getIntervalMillis()); // default is 15min
+  }
+
+  @Test
+  public void testInterval() {
+    RequestSenderTimer timer = new RequestSenderTimer();
+    timer.setTimerInterval(EventsUploadInterval.AT_MOST_5_MINUTES);
+    assertEquals(5*60*1000, timer.getIntervalMillis());
+
+    timer.setTimerInterval(EventsUploadInterval.AT_MOST_10_MINUTES);
+    assertEquals(10*60*1000, timer.getIntervalMillis());
+
+    timer.setTimerInterval(EventsUploadInterval.AT_MOST_15_MINUTES);
+    assertEquals(15*60*1000, timer.getIntervalMillis());
+  }
+
+  /**
+   * Tests if timer operation is scheduled successfully.
+   */
+  @Test
+  public void testStartTimer() {
+    Runnable timerOperation = new Runnable() {
+      @Override
+      public void run() {
+        operationExecuted = true;
+      }
+    };
+
+    RequestSenderTimer timer = Mockito.spy(RequestSenderTimer.class);
+    Mockito.when(timer.createTimerOperation()).thenReturn(timerOperation);
+
+    operationExecuted = false;
+    timer.start();
+    assertTrue(operationExecuted);
+  }
+}