diff --git a/sport_activities_features/area_identification.py b/sport_activities_features/area_identification.py
index 5e013f8..f0ce2d0 100644
--- a/sport_activities_features/area_identification.py
+++ b/sport_activities_features/area_identification.py
@@ -104,7 +104,8 @@ def extract_data_in_area(self) -> dict:
             cur_time = (self.timestamps[i] - self.timestamps[i - 1]).seconds
             distance += cur_distance
             time += cur_time
-            heartrates = np.append(heartrates, self.heartrates[i])
+            if self.heartrates[i]: 
+                heartrates = np.append(heartrates, self.heartrates[i])
             if cur_distance / cur_time > max_speed:
                 max_speed = cur_distance / cur_time
 
diff --git a/sport_activities_features/tests/test_area_identification.py b/sport_activities_features/tests/test_area_identification.py
new file mode 100644
index 0000000..276bd89
--- /dev/null
+++ b/sport_activities_features/tests/test_area_identification.py
@@ -0,0 +1,37 @@
+import numpy as np
+import os
+from unittest import TestCase
+from sport_activities_features.area_identification import AreaIdentification
+from sport_activities_features.tcx_manipulation import TCXFile
+
+class TestAreaIdentification(TestCase):
+    def setUp(self):
+        filename = os.path.join(os.path.dirname(__file__), "data", '15.tcx')
+        tcx_file = TCXFile()
+        self.activity = tcx_file.read_one_file(filename)
+        area_coordinates = np.array([[[10, 10], [10, 50], [50, 50], [50, 10]],
+                                     [[19, 19], [19, 21], [21, 21], [21, 19]]])
+        area = AreaIdentification(self.activity['positions'], self.activity['distances'], self.activity['timestamps'], self.activity['heartrates'], area_coordinates)
+        area.identify_points_in_area()
+        self.data = area.extract_data_in_area()
+
+    def test_distance_correct(self):
+        self.assertAlmostEqual(self.data['distance'], 116367.0, places=1) 
+        
+    def test_time_correct(self):
+        self.assertAlmostEqual(self.data['time'], 17250.0, places=1)
+
+    def test_max_speed_correct(self):
+        self.assertAlmostEqual(self.data['max_speed'], 21.4, places=1)
+
+    def test_avg_speed_correct(self):
+        self.assertAlmostEqual(self.data['avg_speed'], 6.7, places=1)
+
+    def test_min_heartrate_correct(self):
+        self.assertAlmostEqual(self.data['min_heartrate'], 95.0, places=1)
+
+    def test_max_heartrate_correct(self):
+        self.assertAlmostEqual(self.data['max_heartrate'], 200.0, places=1)
+
+    def test_avg_heartrate_correct(self):
+        self.assertAlmostEqual(self.data['avg_heartrate'], 140.6, places=1)
\ No newline at end of file