Added calculateDistance between two locations and first tests.

lib/forms/profile_category_form.dart

@@ -1,5 +1,5 @@
 import 'package:flutter/material.dart';
-import '../helper.dart';
+import '../utils/helper.dart';
 
 class ProfileCategoryForm<T> extends StatefulWidget {
   final String title;

lib/models/location.dart

@@ -1,5 +1,5 @@
 import '../constants.dart';
-import '../helper.dart';
+import '../utils/math.dart';
 
 class MyLocation {
   final String street;
@@ -43,8 +43,8 @@ class MyLocation {
   /// Returns: locality, country. In case of an error: latitude, longitude.
   String toStringDegree() {
     try {
-      String latResult = convertDecimalToDMS(latitude!);
+      String latResult = convertDecimalToDMS(latitude!, isLatitude: true);
-      String longResult = convertDecimalToDMS(longitude!);
+      String longResult = convertDecimalToDMS(longitude!, isLatitude: false);
       return '$latResult, $longResult';
     } catch (e) {
       // on error return origin values

lib/pages/login_page.dart

@@ -2,7 +2,7 @@ import 'package:firebase_auth/firebase_auth.dart';
 import 'package:flutter/material.dart';
 import '../components/my_button.dart';
 import '../components/my_textfield.dart';
-import '../helper.dart';
+import '../utils/helper.dart';
 import '../services/auth/auth_service.dart';
 
 class LoginPage extends StatelessWidget {

lib/pages/register_page.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:firebase_auth/firebase_auth.dart';
 import '../components/my_button.dart';
 import '../components/my_textfield.dart';
-import '../helper.dart';
+import '../utils/helper.dart';
 import '../services/auth/auth_service.dart';
 import '../services/user_service.dart';
 

lib/services/chat/chat_service.dart

@@ -2,7 +2,7 @@ import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:firebase_auth/firebase_auth.dart';
 
 import '../../constants.dart';
-import '../../helper.dart';
+import '../../utils/helper.dart';
 import '../../models/message.dart';
 
 class ChatService {

lib/utils/helper.dart

@@ -17,27 +17,6 @@ String getCompoundId(List<String> ids){
   return ids.join('_');
 }
 
-///
-/// Convert decimal coordinate to degrees minutes seconds (DMS).
-///
-String convertDecimalToDMS(double decimalValue) {
-  bool isNegative = decimalValue < 0;
-  double absoluteValue = decimalValue.abs();
-
-  int degrees = absoluteValue.toInt();
-  double minutesDecimal = (absoluteValue - degrees) * 60;
-  int minutes = minutesDecimal.toInt();
-  double secondsDecimal = (minutesDecimal - minutes) * 60;
-  double seconds = double.parse(secondsDecimal.toStringAsFixed(2));
-
-  String direction = isNegative
-      ? (decimalValue < 0 ? 'W' : 'S')
-      : (decimalValue >= 0 ? (degrees != 0 ? 'N' : 'E') : '');
-
-  // return formatted string
-  return '${degrees.abs()}° ${minutes.abs()}\' ${seconds.abs()}" $direction';
-}
-
 ///
 /// Get the [displayName] of our own Enumerations.
 ///

lib/utils/math.dart

@@ -0,0 +1,47 @@
+import 'dart:math';
+
+///
+/// Convert decimal coordinate to degrees minutes seconds (DMS).
+///
+String convertDecimalToDMS(double decimalValue, {required bool isLatitude}) {
+  bool isNegative = decimalValue < 0;
+  double absoluteValue = decimalValue.abs();
+
+  int degrees = absoluteValue.toInt();
+  double minutesDecimal = (absoluteValue - degrees) * 60;
+  int minutes = minutesDecimal.toInt();
+  double secondsDecimal = (minutesDecimal - minutes) * 60;
+  double seconds = double.parse(secondsDecimal.toStringAsFixed(2));
+
+  String direction;
+  if (isLatitude) {
+    direction = isNegative ? 'S' : 'N';
+  } else {
+    direction = isNegative ? 'W' : 'E';
+  }
+
+  // return formatted string
+  return '${degrees.abs()}° ${minutes.abs()}\' ${seconds.abs().toStringAsFixed(2)}" $direction';
+}
+
+///
+/// Distance in kilometers between two location coordinates
+///
+double calculateDistance(double lat1, double lon1, double lat2, double lon2) {
+  const R = 6371; // earth radius in kilometers
+
+  // distance between latitudes and longitudes
+  final dLat = _degreesToRadians(lat2 - lat1);
+  final dLon = _degreesToRadians(lon2 - lon1);
+
+  final a = sin(dLat / 2) * sin(dLat / 2) +
+      cos(_degreesToRadians(lat1)) * cos(_degreesToRadians(lat2)) *
+          sin(dLon / 2) * sin(dLon / 2);
+  final c = 2 * atan2(sqrt(a), sqrt(1 - a));
+
+  return R * c;
+}
+
+double _degreesToRadians(double degrees) {
+  return degrees * pi / 180;
+}

test/helper_test.dart

@@ -0,0 +1,81 @@
+import 'package:cofounderella/utils/helper.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  group('getCompoundId', () {
+    test('returns correct compound ID for a sorted list', () {
+      List<String> ids = ['id3', 'id1', 'id2'];
+      String result = getCompoundId(ids);
+      expect(result, 'id1_id2_id3');
+    });
+
+    test('returns correct compound ID for an already sorted list', () {
+      List<String> ids = ['id1', 'id2', 'id3'];
+      String result = getCompoundId(ids);
+      expect(result, 'id1_id2_id3');
+    });
+
+    test('returns correct compound ID for a single element list', () {
+      List<String> ids = ['id1'];
+      String result = getCompoundId(ids);
+      expect(result, 'id1');
+    });
+
+    test('returns correct compound ID for empty elements', () {
+      List<String> ids = ['id1','','id2',''];
+      String result = getCompoundId(ids);
+      expect(result, '__id1_id2');
+    });
+
+    test('returns correct compound ID for an empty list', () {
+      List<String> ids = [];
+      String result = getCompoundId(ids);
+      expect(result, '');
+    });
+  });
+
+  group('equalContent', () {
+    test('returns true for lists with the same content in the same order', () {
+      List<dynamic> list1 = [1, 2, 3];
+      List<dynamic> list2 = [1, 2, 3];
+      bool result = equalContent(list1, list2);
+      expect(result, true);
+    });
+
+    test('returns true for lists with the same content in different orders',
+        () {
+      List<dynamic> list1 = [1, 2, 3];
+      List<dynamic> list2 = [3, 1, 2];
+      bool result = equalContent(list1, list2);
+      expect(result, true);
+    });
+
+    test('returns false for lists with different content', () {
+      List<dynamic> list1 = [1, 2, 3];
+      List<dynamic> list2 = [1, 2, 4];
+      bool result = equalContent(list1, list2);
+      expect(result, false);
+    });
+
+    test('returns false for lists with different lengths', () {
+      List<dynamic> list1 = [1, 2, 3];
+      List<dynamic> list2 = [1, 2];
+      bool result = equalContent(list1, list2);
+      expect(result, false);
+    });
+
+    test('returns true for empty lists', () {
+      List<dynamic> list1 = [];
+      List<dynamic> list2 = [];
+      bool result = equalContent(list1, list2);
+      expect(result, true);
+    });
+
+    test('returns false for one empty and one non-empty list', () {
+      List<dynamic> list1 = [];
+      List<dynamic> list2 = [1];
+      bool result = equalContent(list1, list2);
+      expect(result, false);
+    });
+  });
+}

test/math_test.dart

@@ -0,0 +1,88 @@
+import 'package:cofounderella/utils/math.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+
+void main() {
+  group('Distance Calculation', () {
+    test('returns correct distance between Berlin and Paris', () {
+      // Example coordinates for Berlin and Paris
+      double berlinLat = 52.516216;
+      double berlinLon =  13.377646;
+      double parisLat = 48.858119;
+      double parisLon = 2.294483;
+
+      // Calculated distance between Berlin and Paris
+      double distance = calculateDistance(berlinLat, berlinLon, parisLat, parisLon);
+
+      // Expected approximate distance in kilometers
+      double expectedDistance = 879.1;
+
+      // Comparison of both distances
+      expect(distance, closeTo(expectedDistance, 1.0));
+    });
+
+    test('returns correct distance between same coordinates', () {
+      double lat = 49.469548;
+      double lon = 8.48243;
+
+      double distance = calculateDistance(lat, lon, lat, lon);
+
+      expect(distance, equals(0.0));
+    });
+
+    test('returns correct distance for long distances', () {
+      // Example coordinates for New York and Sydney
+      double newYorkLat = 40.7128;
+      double newYorkLon = -74.0060;
+      double sydneyLat = -33.8688;
+      double sydneyLon = 151.2093;
+
+      double distance = calculateDistance(newYorkLat, newYorkLon, sydneyLat, sydneyLon);
+      double expectedDistance = 15988; // in kilometers
+
+      // Comparison of the calculated and expected distance
+      // with a tolerance of 10 due to the enormous distance
+      expect(distance, closeTo(expectedDistance, 10.0));
+    });
+  });
+
+
+
+  group('Coordinate Conversion', () {
+    test('converts positive latitude correctly', () {
+      double decimalValue = 40.7128;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: true);
+      expect(result, '40° 42\' 46.08" N');
+    });
+
+    test('converts negative latitude correctly', () {
+      double decimalValue = -40.7128;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: true);
+      expect(result, '40° 42\' 46.08" S');
+    });
+
+    test('converts positive longitude correctly', () {
+      double decimalValue = 74.0060;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: false);
+      expect(result, '74° 0\' 21.60" E');
+    });
+
+    test('converts negative longitude correctly', () {
+      double decimalValue = -74.0060;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: false);
+      expect(result, '74° 0\' 21.60" W');
+    });
+
+    test('handles zero latitude correctly', () {
+      double decimalValue = 0.0;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: true);
+      expect(result, '0° 0\' 0.00" N');
+    });
+
+    test('handles zero longitude correctly', () {
+      double decimalValue = 0.0;
+      String result = convertDecimalToDMS(decimalValue, isLatitude: false);
+      expect(result, '0° 0\' 0.00" E');
+    });
+  });
+}