[Android] BackgroundTaskScheduler reschedule implementation

components/background_task_scheduler/android/junit/src/org/chromium/components/background_task_scheduler/BackgroundTaskSchedulerTest.java

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.components.background_task_scheduler;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.doNothing;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.test.util.Feature;
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+import java.util.concurrent.TimeUnit;
+
+/** Unit tests for {@link BackgroundTaskScheduler}. */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class BackgroundTaskSchedulerTest {
+    private static final TaskInfo TASK =
+            TaskInfo.createOneOffTask(
+                            TaskIds.TEST, TestBackgroundTask.class, TimeUnit.DAYS.toMillis(1))
+                    .build();
+
+    @Mock
+    private BackgroundTaskSchedulerDelegate mDelegate;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        ContextUtils.initApplicationContextForTests(RuntimeEnvironment.application);
+        BackgroundTaskSchedulerFactory.setSchedulerForTesting(
+                new BackgroundTaskScheduler(mDelegate));
+        TestBackgroundTask.reset();
+    }
+
+    @Test
+    @Feature({"BackgroundTaskScheduler"})
+    public void testScheduleTask() {
+        doReturn(true).when(mDelegate).schedule(eq(RuntimeEnvironment.application), eq(TASK));
+        BackgroundTaskSchedulerFactory.getScheduler().schedule(
+                RuntimeEnvironment.application, TASK);
+        assertFalse(BackgroundTaskSchedulerPrefs.getScheduledTasks().contains(

[nyquist, 2017/04/18 22:33:03]

It's unclear to me why this should be false. Don't we unconditionally add a task
to these prefs? I thought we only removed things from the set when we cancel a
task, or reschedule all of them?

[fgorski, 2017/04/20 19:09:58]

Good catch. This was a test bug.

I was thinking we shouldn't be unconditional thou, so I added an extra test.

+                TASK.getBackgroundTaskClass()));
+        verify(mDelegate, times(1)).schedule(eq(RuntimeEnvironment.application), eq(TASK));
+    }
+
+    @Test
+    @Feature({"BackgroundTaskScheduler"})
+    public void testCancel() {
+        BackgroundTaskSchedulerPrefs.addScheduledTask(TASK);
+
+        doNothing().when(mDelegate).cancel(eq(RuntimeEnvironment.application), eq(TaskIds.TEST));
+        BackgroundTaskSchedulerFactory.getScheduler().cancel(
+                RuntimeEnvironment.application, TaskIds.TEST);
+        assertFalse(BackgroundTaskSchedulerPrefs.getScheduledTasks().contains(
+                TASK.getBackgroundTaskClass()));
+        verify(mDelegate, times(1)).cancel(eq(RuntimeEnvironment.application), eq(TaskIds.TEST));
+    }
+
+    @Test
+    @Feature({"BackgroundTaskScheduler"})
+    public void testRescheduleTasks() {
+        BackgroundTaskSchedulerPrefs.addScheduledTask(TASK);
+
+        assertEquals(0, TestBackgroundTask.getRescheduleCalls());
+        assertFalse(BackgroundTaskSchedulerPrefs.getScheduledTasks().isEmpty());
+        BackgroundTaskSchedulerFactory.getScheduler().reschedule(RuntimeEnvironment.application);
+
+        assertEquals(1, TestBackgroundTask.getRescheduleCalls());
+        assertTrue(BackgroundTaskSchedulerPrefs.getScheduledTasks().isEmpty());
+    }
+}