In TrackWriterImpl, write an empty track if the track has no valid locations.

MyTracks/src/com/google/android/apps/mytracks/io/file/TrackWriterImpl.java

@@ -317,22 +317,16 @@ class TrackWriterImpl implements TrackWriter {
     LocationIterator it = providerUtils.getTrackPointLocationIterator(track.getId(), 0, false,
         locationFactory);
     try {
-      if (!it.hasNext()) {
-        // Writes an empty track
-        writer.writeBeginTrack(null);
-        writer.writeEndTrack(null);
-        return;
-      }
       int pointNumber = 0;
       while (it.hasNext()) {
-        Location loc = it.next();
+        Location location = it.next();
         if (Thread.interrupted()) {
           throw new InterruptedException();
         }
 
         pointNumber++;
 
-        boolean isValid = LocationUtils.isValidLocation(loc);
+        boolean isValid = LocationUtils.isValidLocation(location);
         boolean validSegment = isValid && isLastValid;
         if (!wroteFirst && validSegment) {
           // Found the first two consecutive points which are valid
@@ -351,7 +345,7 @@ class TrackWriterImpl implements TrackWriter {
           }
 
           // Write the current point
-          writer.writeLocation(loc);
+          writer.writeLocation(location);
           if (onWriteListener != null) {
             onWriteListener.onWrite(pointNumber, track.getNumberOfPoints());
           }
@@ -371,6 +365,10 @@ class TrackWriterImpl implements TrackWriter {
       }
       if (wroteFirst) {
         writer.writeEndTrack(locationFactory.lastLocation);
+      } else {
+        // Writes an empty track
+        writer.writeBeginTrack(null);
+        writer.writeEndTrack(null);
       }
     } finally {
       it.close();

MyTracksTest/src/com/google/android/apps/mytracks/io/file/TrackWriterTest.java

@@ -237,6 +237,34 @@ public class TrackWriterTest extends AndroidTestCase {
     mocksControl.verify();
   }
 
+  /**
+   * Tests when a track only contains invalid locations. Make sure an empty
+   * track is written.
+   */
+  public void testWriteDocument_oneInvalidLocation() throws Exception {
+    writer = new TrackWriterImpl(getContext(), providerUtils, track, formatWriter);
+
+    Location[] locs = { new Location("fake0") };
+    fillLocations(locs);
+
+    // Make location invalid
+    locs[0].setLatitude(100);
+
+    assertEquals(locs.length, providerUtils.bulkInsertTrackPoint(locs, locs.length, TRACK_ID));
+
+    formatWriter.writeHeader();
+    formatWriter.writeBeginTrack(null);
+    formatWriter.writeEndTrack(null);
+    formatWriter.writeFooter();
+    formatWriter.close();
+
+    mocksControl.replay();
+    writer.writeDocument();
+
+    assertTrue(writer.wasSuccess());
+    mocksControl.verify();
+  }
+
   public void testWriteDocument() throws Exception {
     writer = new TrackWriterImpl(getContext(), providerUtils, track, formatWriter);