added test and exception if null point exist during operations (#513)

* added test and exception if null point exist during operations

* fixed checkstyle

Author: Cameron Mace

mapbox/libjava-geojson/src/main/java/com/mapbox/services/commons/geojson/Point.java

@@ -93,4 +93,31 @@ public String toJson() {
     gson.registerTypeAdapter(Position.class, new PositionSerializer());
     return gson.create().toJson(this);
   }
-}
+
+  @Override
+  public boolean equals(Object object) {
+    if (!(object instanceof Point)) {
+      return false;
+    }
+    if (this == object) {
+      return true;
+    }
+    Point point = (Point) object;
+    return coordinates.equals(point.coordinates);
+  }
+
+  @Override
+  public int hashCode() {
+    int result = type.hashCode();
+    result = 31 * result + (coordinates != null ? coordinates.hashCode() : 0);
+    return result;
+  }
+
+  @Override
+  public String toString() {
+    return "Point{"
+      + "type='" + type + '\''
+      + ", coordinates=" + coordinates
+      + '}';
+  }
+}

mapbox/libjava-services/src/main/java/com/mapbox/services/api/utils/turf/TurfMisc.java

@@ -52,6 +52,12 @@ public static LineString lineSlice(Point startPt, Point stopPt, Feature line) th
   public static LineString lineSlice(Point startPt, Point stopPt, LineString line) throws TurfException {
     List<Position> coords = line.getCoordinates();
 
+    if (coords.size() < 2) {
+      throw new TurfException("Turf lineSlice requires a LineString made up of at least 2 coordinates.");
+    } else if (startPt.equals(stopPt)) {
+      throw new TurfException("Start and stop points in Turf lineSlice cannot equal each other.");
+    }
+
     Feature startVertex = pointOnLine(startPt, coords);
     Feature stopVertex = pointOnLine(stopPt, coords);
     List<Feature> ends = new ArrayList<>();

mapbox/libjava-services/src/test/java/com/mapbox/services/api/turf/TurfMeasurementTest.java

@@ -17,6 +17,8 @@
 import org.junit.rules.ExpectedException;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertEquals;
@@ -72,6 +74,16 @@ public void testDistance() throws TurfException {
     TurfMeasurement.distance(pt1, pt2, "blah");
   }
 
+  @Test
+  public void lineDistance_returnsZeroWhenRouteIsPoint() throws Exception {
+    List<Position> coords = new ArrayList<>();
+    coords.add(Position.fromCoordinates(1.0, 1.0));
+
+    LineString lineString = LineString.fromCoordinates(coords);
+    double distance = TurfMeasurement.lineDistance(lineString, TurfConstants.UNIT_METERS);
+    assertEquals(0, distance, DELTA);
+  }
+
   @Test
   public void testLineDistanceWithGeometries() throws IOException, TurfException {
     Feature route1 = Feature.fromJson(loadJsonFixture("turf-line-distance", "route1.geojson"));
@@ -171,6 +183,17 @@ public void testMidpointPositionToPoint() throws TurfException {
         Point.fromCoordinates(mid), TurfConstants.UNIT_MILES), DELTA);
   }
 
+  @Test
+  public void turfAlong_returnsZeroWhenRouteIsPoint() throws Exception {
+    List<Position> coords = new ArrayList<>();
+    coords.add(Position.fromCoordinates(1.0, 1.0));
+
+    LineString lineString = LineString.fromCoordinates(coords);
+    Point point = TurfMeasurement.along(lineString, 0, TurfConstants.UNIT_METERS);
+    assertEquals(1.0, point.getCoordinates().getLatitude(), DELTA);
+    assertEquals(1.0, point.getCoordinates().getLongitude(), DELTA);
+  }
+
   @Test
   public void testTurfAlong() throws IOException, TurfException {
     Feature feature = Feature.fromJson(loadJsonFixture("turf-along", "dc-line.geojson"));

mapbox/libjava-services/src/test/java/com/mapbox/services/api/turf/TurfMiscTest.java

@@ -9,19 +9,51 @@
 import com.mapbox.services.commons.geojson.Point;
 import com.mapbox.services.commons.models.Position;
 
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.hamcrest.Matchers.startsWith;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 public class TurfMiscTest extends BaseTurf {
 
+  @Rule
+  public ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void lineSlice_throwsStartStopPointException() throws Exception {
+    thrown.expect(TurfException.class);
+    thrown.expectMessage(startsWith("Turf lineSlice requires a LineString made up of at least 2 coordinates."));
+
+    List<Position> coords = new ArrayList<>();
+    coords.add(Position.fromCoordinates(1.0, 1.0));
+    Point point = Point.fromCoordinates(new double[] {1.0, 1.0});
+    Point point2 = Point.fromCoordinates(new double[] {2.0, 2.0});
+    LineString lineString = LineString.fromCoordinates(coords);
+    TurfMisc.lineSlice(point, point2, lineString);
+  }
+
+  @Test
+  public void lineSlice_throwLineMustContainTwoOrMorePoints() throws Exception {
+    thrown.expect(TurfException.class);
+    thrown.expectMessage(startsWith("Start and stop points in Turf lineSlice cannot equal each other."));
+
+    List<Position> coords = new ArrayList<>();
+    coords.add(Position.fromCoordinates(1.0, 1.0));
+    coords.add(Position.fromCoordinates(2.0, 2.0));
+    Point point = Point.fromCoordinates(new double[] {1.0, 1.0});
+    LineString lineString = LineString.fromCoordinates(coords);
+    TurfMisc.lineSlice(point, point, lineString);
+  }
+
   @Test
   public void testTurfLineSliceLine1() throws IOException, TurfException {
     Point start = Point.fromCoordinates(Position.fromCoordinates(-97.79617309570312, 22.254624939561698));