diff --git a/.env.example b/.env.example
index 45f410b..5ae28bc 100644
--- a/.env.example
+++ b/.env.example
@@ -5,6 +5,7 @@ USERNAME=
 PASSWORD=
 
 SESSION_COOKIE_NAME=
+MAX_RECORD_DAYS=
 
 # NEW DATABASE URI
-SQLALCHEMY_DATABASE_URI='mysql+mysqlconnector://user:pass@host/database'
\ No newline at end of file
+SQLALCHEMY_DATABASE_URI='mysql+mysqlconnector://user:pass@host/database'
diff --git a/.github/workflows/python-app.yml b/.github/workflows/python-app.yml
new file mode 100644
index 0000000..48ce960
--- /dev/null
+++ b/.github/workflows/python-app.yml
@@ -0,0 +1,24 @@
+# This workflow will install Python dependencies, run tests and lint with a single version of Python
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
+
+name: Python application
+
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python 3.8
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.8
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+    - name: Run tests
+      run: |
+        python -m unittest discover
diff --git a/README.md b/README.md
index b66c025..8b76563 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,20 @@ Server is based on **Flask** and few extensions:
 
 Database: **MySQL**
 
+## Executing
+
+First of all, activate virtual environment with:
+
+`source venv/bin/activate`
+
+To start the server run:
+
+`python run.py`
+
+To start tests run:
+
+`python -m unittest tests`
+
 ## Credits
 
 All credits to @andrew4ever
diff --git a/common/AQICalculator.py b/common/AQICalculator.py
index 7731d47..f23a6cf 100644
--- a/common/AQICalculator.py
+++ b/common/AQICalculator.py
@@ -2,6 +2,9 @@
 # In future old backend will be replaced by this new project and aqi calculator will be refactored
 
 import math
+from os import environ
+from datetime import datetime
+
 import mysql.connector
 
 
@@ -34,13 +37,19 @@ def calculate_aqi(self):
                 continue
 
             self.cursor.execute(
-                "SELECT * FROM `sensor_record` WHERE `sensor_id` = {}".format(
+                "SELECT * FROM `sensor_record` WHERE `sensor_id` = {} ORDER BY `created_at` DESC".format(
                     sensor[0])
             )
             record = self.cursor.fetchone()
 
-            if record:
+            if not record:
+                continue
+
+            timedelta = datetime.now() - record[2]
+
+            if timedelta.days < int(environ.get('MAX_RECORD_DAYS')):
                 records.append(record)
+                print(sensor[0], record)
 
         # arrange records to squares
         squares = {}
@@ -52,6 +61,12 @@ def calculate_aqi(self):
 
             squares[square_center].append(record)
 
+        self.cursor.execute("SELECT * FROM `sensor_value_type`")
+        types = self.cursor.fetchall()
+        used_ids = [value_type[0]
+                    for value_type in types if value_type[-2] == 1]
+        types = {value_type[0]: value_type for value_type in types}
+
         # get aqi for each square
         for center, records in squares.items():
             # prepare dataset
@@ -61,12 +76,6 @@ def calculate_aqi(self):
                     "SELECT * FROM `sensor_value` WHERE `record_id` = {}".format(record[0]))
                 values = self.cursor.fetchall()
 
-                self.cursor.execute("SELECT * FROM `sensor_value_type`")
-                types = self.cursor.fetchall()
-                used_ids = [value_type[0]
-                            for value_type in types if value_type[-2] == 1]
-                types = {value_type[0]: value_type for value_type in types}
-
                 for value in values:
                     if value[2] not in used_ids:
                         continue
diff --git a/models/area.py b/models/area.py
index 3abfd6b..1871a65 100644
--- a/models/area.py
+++ b/models/area.py
@@ -36,9 +36,9 @@ class AreaModel(db.Model):
     )
 
     def __repr__(self):
-        return '<Area {}>'.format(self._string_coords())
+        return '<Area {}>'.format(self.string_coords())
 
-    def _string_coords(self):
+    def string_coords(self):
         return str(self.latitude) + '-' + str(self.longitude)
 
     def as_dict(self):
diff --git a/resources/area.py b/resources/area.py
index 727fcb5..3b3a5a1 100644
--- a/resources/area.py
+++ b/resources/area.py
@@ -12,7 +12,7 @@ def get(self):
         areas = AreaModel.query \
             .filter_by(latitude=latitude) \
             .filter_by(longitude=longitude) \
-            .limit(10).order_by(desc(AreaModel.created)).all()
+            .order_by(desc(AreaModel.created)).all()
 
         if not areas:
             return {'code': 404, 'message': 'Area not found'}, 404
diff --git a/resources/map.py b/resources/map.py
index 8e1206a..7592d99 100644
--- a/resources/map.py
+++ b/resources/map.py
@@ -1,3 +1,6 @@
+from datetime import datetime
+from os import environ
+
 from flask_restful import Resource
 from sqlalchemy import desc
 
@@ -17,6 +20,12 @@ def get(self):
             if (a['latitude'], a['longitude']) in areas_coords:
                 continue
 
+            timedelta = datetime.now() - \
+                datetime.strptime(a['created'], '%Y-%m-%d %H:%M:%S')
+
+            if timedelta.days >= int(environ.get('MAX_RECORD_DAYS')):
+                continue
+
             areas_coords.append((a['latitude'], a['longitude']))
             areas_list.append(area.as_dict())
 
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..1b3bd4c
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,3 @@
+from tests.models.area import AreaModelTest
+from tests.resources.area import AreaResourceTest
+from tests.resources.map import MapResourceTest
diff --git a/tests/models/area.py b/tests/models/area.py
new file mode 100644
index 0000000..184c2b3
--- /dev/null
+++ b/tests/models/area.py
@@ -0,0 +1,43 @@
+import unittest
+
+from models import AreaModel
+
+
+class AreaModelTest(unittest.TestCase):
+    def test_as_dict(self):
+        data = {
+            'aqi': 42,
+            'latitude': '50.442',
+            'longitude': '30.91'
+        }
+
+        result = AreaModel(**data).as_dict()
+        del result['created']
+        del result['id']
+
+        self.assertEqual(result, data)
+
+    def test_string_coords(self):
+        data = {
+            'aqi': 42,
+            'latitude': '50.442',
+            'longitude': '30.91'
+        }
+
+        result = AreaModel(**data).string_coords()
+
+        self.assertEqual(result, self.string_coords(data))
+
+    def test_repr(self):
+        data = {
+            'aqi': 42,
+            'latitude': '50.442',
+            'longitude': '30.91'
+        }
+
+        result = str(AreaModel(**data))
+
+        self.assertEqual(result, '<Area {}>'.format(self.string_coords(data)))
+
+    def string_coords(self, data):
+        return data['latitude'] + '-' + data['longitude']
diff --git a/tests/resources/area.py b/tests/resources/area.py
new file mode 100644
index 0000000..5f1ec31
--- /dev/null
+++ b/tests/resources/area.py
@@ -0,0 +1,7 @@
+import unittest
+
+from resources import AreaResource
+
+
+class AreaResourceTest(unittest.TestCase):
+    pass
diff --git a/tests/resources/map.py b/tests/resources/map.py
new file mode 100644
index 0000000..2dd1fb6
--- /dev/null
+++ b/tests/resources/map.py
@@ -0,0 +1,7 @@
+import unittest
+
+from resources import Map
+
+
+class MapResourceTest(unittest.TestCase):
+    pass