Code improvements

* Replace unchecked casts with checked casts
 * remove Utility.finViewById
 * Fix return activity checking
 * Create UserAction enum
 * Fix typos
 * Add instrumented test for error info
 * ErrorInfo make fields final
 * Log exception using logger
 * Add inherited annotations
 * Resolve deprecation warnings
 * Remove unused methods from utility
 * Reformat code
 * Remove unused methods from Utility and improve getFileExt
 * Create OnScrollBelowItemsListener

app/src/test/java/org/schabi/newpipe/report/ErrorActivityTest.java

@@ -0,0 +1,38 @@
+package org.schabi.newpipe.report;
+
+import android.app.Activity;
+
+import org.junit.Test;
+import org.schabi.newpipe.MainActivity;
+import org.schabi.newpipe.RouterActivity;
+import org.schabi.newpipe.fragments.detail.VideoDetailFragment;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+/**
+ * Unit tests for {@link ErrorActivity}
+ */
+public class ErrorActivityTest {
+    @Test
+    public void getReturnActivity() throws Exception {
+        Class<? extends Activity> returnActivity;
+        returnActivity = ErrorActivity.getReturnActivity(MainActivity.class);
+        assertEquals(MainActivity.class, returnActivity);
+
+        returnActivity = ErrorActivity.getReturnActivity(RouterActivity.class);
+        assertEquals(RouterActivity.class, returnActivity);
+
+        returnActivity = ErrorActivity.getReturnActivity(null);
+        assertNull(returnActivity);
+
+        returnActivity = ErrorActivity.getReturnActivity(Integer.class);
+        assertEquals(MainActivity.class, returnActivity);
+
+        returnActivity = ErrorActivity.getReturnActivity(VideoDetailFragment.class);
+        assertEquals(MainActivity.class, returnActivity);
+    }
+
+
+
+}

app/src/test/java/us/shandian/giga/get/get/DownloadManagerImplTest.java

@@ -31,18 +31,18 @@ import static org.mockito.Mockito.when;
 public class DownloadManagerImplTest {
 
     private DownloadManagerImpl downloadManager;
-    private DownloadDataSource dowloadDataSource;
+    private DownloadDataSource downloadDataSource;
     private ArrayList<DownloadMission> missions;
 
     @org.junit.Before
     public void setUp() throws Exception {
-        dowloadDataSource = mock(DownloadDataSource.class);
+        downloadDataSource = mock(DownloadDataSource.class);
         missions = new ArrayList<>();
         for(int i = 0; i < 50; ++i){
             missions.add(generateFinishedDownloadMission());
         }
-        when(dowloadDataSource.loadMissions()).thenReturn(new ArrayList<>(missions));
-        downloadManager = new DownloadManagerImpl(new ArrayList<String>(), dowloadDataSource);
+        when(downloadDataSource.loadMissions()).thenReturn(new ArrayList<>(missions));
+        downloadManager = new DownloadManagerImpl(new ArrayList<String>(), downloadDataSource);
     }
 
     @Test(expected = NullPointerException.class)
@@ -82,10 +82,10 @@ public class DownloadManagerImplTest {
             missions.add(mission);
         }
 
-        dowloadDataSource = mock(DownloadDataSource.class);
-        when(dowloadDataSource.loadMissions()).thenReturn(new ArrayList<>(missions));
-        downloadManager = new DownloadManagerImpl(new ArrayList<String>(), dowloadDataSource);
-        verify(dowloadDataSource, times(1)).loadMissions();
+        downloadDataSource = mock(DownloadDataSource.class);
+        when(downloadDataSource.loadMissions()).thenReturn(new ArrayList<>(missions));
+        downloadManager = new DownloadManagerImpl(new ArrayList<String>(), downloadDataSource);
+        verify(downloadDataSource, times(1)).loadMissions();
 
         assertEquals(50, downloadManager.getCount());