LazMapViewer: Add unit test for distance calculation

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@8793 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/lazmapviewer/unittests/mvmisctests_engine.pas

@@ -10,6 +10,7 @@ uses
 type
   TMiscTests_Engine= class(TTestCase)
   published
+    procedure Test_Distance;
     procedure Test_LatToStr_DMS;
     procedure Test_LatToStr_Deg;
     procedure Test_LonToStr_DMS;
@@ -23,6 +24,29 @@ implementation
 uses
   Math, mvEngine;
 
+type
+  TDistanceRec = record
+    Name1: String;
+    Lat1, Lon1: Double;
+    Name2: String;
+    Lat2, Lon2: Double;
+    Distance_km: Double;
+  end;
+
+const
+  Distance_TestData: array[0..2] of TDistanceRec = (
+    // Calculated on https://keisan.casio.com/exec/system/1224587128 for R=6378km
+    (Name1: 'Sydney'; Lat1:-33.865143; Lon1:151.209900;
+     Name2: 'San Francisco'; Lat2:37.828724; Lon2:-122.355537;
+     Distance_km: 11968),
+    (Name1: 'London'; Lat1: 51.503368; Lon1: -0.127721;
+     Name2: 'Istanbul'; Lat2: 41.276901; Lon2: 28.729324;
+     Distance_km: 2468.6),
+    (Name1: 'Tokyo'; Lat1:35.652832; Lon1:139.839478;
+     Name2: 'Singapore'; Lat2:1.290270; Lon2:103.851959;
+     Distance_km: 5331.97)
+  );
+
 type
   TLatLonRec = record
     Name: String;
@@ -38,9 +62,6 @@ type
     Lon_S: Double;
   end;
 
-var
-  PointFormatsettings: TFormatSettings;
-
 const
   LatLon_TestData: array[0..7] of TLatLonRec = (
     (Name:'Sydney';   // https://www.latlong.net/place/sydney-nsw-australia-700.html
@@ -70,6 +91,25 @@ const
   );
 
 
+var
+  PointFormatsettings: TFormatSettings;
+
+procedure TMiscTests_Engine.Test_Distance;
+const
+  TOLERANCE = 2;
+  RADIUS = 6378; // Earth radius in km, as used by the references
+var
+  i: Integer;
+begin
+  for i := 0 to High(Distance_TestData) do
+    with Distance_TestData[i] do
+      AssertEquals(
+        'Distance mismatch between ' + Name1 + ' and ' + Name2,
+        Distance_km,
+        HaverSineDist(Lat1, Lon1, Lat2, Lon2, RADIUS), TOLERANCE
+      );
+end;
+
 procedure TMiscTests_Engine.Test_LatToStr_Deg;
 const
   NO_DMS = false;