Import: segments might contain no TrackPoints.

#316.

src/androidTest/java/de/dennisguse/opentracks/content/DescriptionGeneratorTest.java

@@ -67,7 +67,7 @@ public class DescriptionGeneratorTest {
         stats.setMaxElevation(550);
         stats.setMinElevation(-500);
         stats.setTotalElevationGain(6000f);
-        stats.setTotalElevationLoss(6000);
+        stats.setTotalElevationLoss(6000f);
         stats.setStartTime(START_TIME);
         track.setTrackStatistics(stats);
         track.setCategory("hiking");
@@ -105,7 +105,7 @@ public class DescriptionGeneratorTest {
         stats.setMaxElevation(Double.POSITIVE_INFINITY);
         stats.setMinElevation(Double.NEGATIVE_INFINITY);
         stats.setTotalElevationGain(6000f);
-        stats.setTotalElevationLoss(6000);
+        stats.setTotalElevationLoss(6000f);
         stats.setStartTime(START_TIME);
         track.setTrackStatistics(stats);
         track.setCategory("hiking");

src/androidTest/java/de/dennisguse/opentracks/stats/TrackStatisticsTest.java

@@ -24,6 +24,7 @@ import java.time.Duration;
 import java.time.Instant;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
 
 /**
  * Tests for {@link TrackStatistics}.
@@ -41,8 +42,32 @@ public class TrackStatisticsTest {
         statistics = new TrackStatistics();
     }
 
+    @Test
+    public void testMerge_no_data() {
+        // given
+        TrackStatistics statistics2 = new TrackStatistics();
+
+        // when
+        statistics.merge(statistics2);
+
+        // then
+        assertNull(statistics.getStartTime());
+        assertNull(statistics.getStopTime());
+        assertEquals(Duration.ofSeconds(0), statistics.getMovingTime());
+        assertEquals(Duration.ofSeconds(0), statistics.getTotalTime());
+
+        assertNull(statistics.getTotalElevationGain());
+        assertNull(statistics.getTotalElevationLoss());
+        assertEquals(Double.NEGATIVE_INFINITY, statistics.getMaxElevation(), 0.0);
+        assertEquals(Double.POSITIVE_INFINITY, statistics.getMinElevation(), 0.0);
+        assertEquals(0.0, statistics.getMaxSpeed(), 0.0);
+        assertEquals(0.0, statistics.getAverageSpeed(), 0.0);
+        assertEquals(0.0, statistics.getAverageMovingSpeed(), 0.0);
+    }
+
     @Test
     public void testMerge() {
+        // given
         TrackStatistics statistics2 = new TrackStatistics();
         statistics.setStartTime(Instant.ofEpochMilli(1000));  // Resulting start time
         statistics.setStopTime(Instant.ofEpochMilli(2500));
@@ -63,8 +88,10 @@ public class TrackStatisticsTest {
         statistics2.setMaxElevation(3575.0);  // Resulting max elevation
         statistics2.setMinElevation(2800.0);
 
+        // when
         statistics.merge(statistics2);
 
+        // then
         assertEquals(Instant.ofEpochMilli(1000), statistics.getStartTime());
         assertEquals(Instant.ofEpochMilli(4000), statistics.getStopTime());
         assertEquals(Duration.ofMillis(2500), statistics.getTotalTime());

src/main/java/de/dennisguse/opentracks/stats/TrackStatistics.java

@@ -48,8 +48,7 @@ public class TrackStatistics {
     // The maximum speed (meters/second) that we believe is valid.
     private double maxSpeed_mps;
     // The total elevation gained (meters).
-    @Nullable
-    private Float totalElevationGain_m;
+    private Float totalElevationGain_m = null;
     // The total elevation lost (meters).
     private Float totalElevationLoss_m = null;
 
@@ -81,8 +80,17 @@ public class TrackStatistics {
      * @param other another statistics data object
      */
     public void merge(TrackStatistics other) {
-        startTime = startTime.isBefore(other.startTime) ? startTime : other.startTime;
-        stopTime = stopTime.isAfter(other.stopTime) ? stopTime : other.stopTime;
+        if (startTime == null) {
+            startTime = other.startTime;
+        } else {
+            startTime = startTime.isBefore(other.startTime) ? startTime : other.startTime;
+        }
+        if (stopTime == null) {
+            stopTime = other.stopTime;
+        } else {
+            stopTime = stopTime.isAfter(other.stopTime) ? stopTime : other.stopTime;
+        }
+
         totalDistance_m += other.totalDistance_m;
         totalTime = totalTime.plus(other.totalTime);
         movingTime = movingTime.plus(other.movingTime);
@@ -120,6 +128,7 @@ public class TrackStatistics {
         setMovingTime(Duration.ofSeconds(0));
         setMaxSpeed(0);
         setTotalElevationGain(null);
+        setTotalElevationLoss(null);
     }
 
     public void reset(Instant startTime) {
@@ -279,8 +288,8 @@ public class TrackStatistics {
         return totalElevationGain_m != null;
     }
 
-    public @Nullable
-    Float getTotalElevationGain() {
+    @Nullable
+    public Float getTotalElevationGain() {
         return totalElevationGain_m;
     }
 
@@ -299,12 +308,12 @@ public class TrackStatistics {
         return totalElevationLoss_m != null;
     }
 
-    public @Nullable
-    Float getTotalElevationLoss() {
+    @Nullable
+    public Float getTotalElevationLoss() {
         return totalElevationLoss_m;
     }
 
-    public void setTotalElevationLoss(float totalElevationLoss_m) {
+    public void setTotalElevationLoss(Float totalElevationLoss_m) {
         this.totalElevationLoss_m = totalElevationLoss_m;
     }