Added and tested distance_to() method

(cherry picked from commit 41c1d3ad)

corsika/detail/framework/geometry/Point.inl

@@ -59,6 +59,10 @@ namespace corsika {
     }
   }
 
+  inline LengthType Point::distance_to(Point const& point) const {
+    return (*this - point).getNorm();
+  }
+
   /// this always returns a QuantityVector as triple
   inline QuantityVector<length_d> Point::getCoordinates(
       CoordinateSystemPtr const& pCS) const {

corsika/framework/geometry/Point.hpp

@@ -65,6 +65,11 @@ namespace corsika {
     LengthType getZ(CoordinateSystemPtr const& pCS) const;
     /** \} **/
 
+    /*
+     * calculates the distance between two points
+     */
+    inline LengthType distance_to(Point const& point) const;
+
     /*!
      * transforms the Point into another CoordinateSystem by changing its
      * coordinates interally

tests/framework/testGeometry.cpp

@@ -314,3 +314,23 @@ TEST_CASE("Geometry Trajectories") {
               .magnitude() == Approx(0).margin(absMargin));
   }
 }
+
+
+TEST_CASE("Point") {
+  //define a known CS
+  CoordinateSystemPtr root = get_root_CoordinateSystem();
+
+  //define known points
+  Point p1(root, {0_m, 0_m, 0_m});
+  Point p2(root, {0_m, 0_m, 5_m});
+  Point p3(root, {1_m, 0_m, 0_m});
+  Point p4(root, {5_m, 0_m, 0_m});
+  Point p5(root, {0_m, 4_m, 0_m});
+  Point p6(root, {0_m, 5_m, 0_m});
+
+  SECTION("Test distance_to() method")
+  //check distance_to() method
+  CHECK(p1.distance_to(p2) / 1_m == Approx(5));
+  CHECK(p3.distance_to(p4) / 1_m == Approx(4));
+  CHECK(p5.distance_to(p6) / 1_m == Approx(1));
+}