diff --git a/sensors/__init__.py b/sensors/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/sensors/co2_sensor.py b/sensors/co2_sensor.py
index 036f86a..a306064 100644
--- a/sensors/co2_sensor.py
+++ b/sensors/co2_sensor.py
@@ -1,6 +1,6 @@
 import random
 import time
-from sensor_base import SensorBase
+from sensors.sensor_base import SensorBase
 
 
 class CO2Sensor(SensorBase):
diff --git a/sensors/noise_sensor.py b/sensors/noise_sensor.py
index e5edfd5..c8eb628 100644
--- a/sensors/noise_sensor.py
+++ b/sensors/noise_sensor.py
@@ -1,6 +1,6 @@
 import random
 import time
-from sensor_base import SensorBase
+from sensors.sensor_base import SensorBase
 
 
 class NoiseSensor(SensorBase):
diff --git a/sensors/occupancy_sensor.py b/sensors/occupancy_sensor.py
index f9ed2c6..4fa6650 100644
--- a/sensors/occupancy_sensor.py
+++ b/sensors/occupancy_sensor.py
@@ -1,6 +1,6 @@
 import random
 import time
-from sensor_base import SensorBase
+from sensors.sensor_base import SensorBase
 
 
 class OccupancySensor(SensorBase):
diff --git a/sensors/temperature_sensor.py b/sensors/temperature_sensor.py
index 8767759..56bbb28 100644
--- a/sensors/temperature_sensor.py
+++ b/sensors/temperature_sensor.py
@@ -1,6 +1,6 @@
 import random
 import time
-from sensor_base import SensorBase
+from sensors.sensor_base import SensorBase
 
 
 class TemperatureSensor(SensorBase):
diff --git a/tests/test_co2_sensor.py b/tests/test_co2_sensor.py
index e69de29..2db603e 100644
--- a/tests/test_co2_sensor.py
+++ b/tests/test_co2_sensor.py
@@ -0,0 +1,46 @@
+import sys
+import os
+import json
+
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+from sensors.co2_sensor import CO2Sensor
+
+def test_generate_reading_returns_valid_json():
+    sensor = CO2Sensor("Room101")
+    reading = sensor.generate_co2_reading()
+
+    parsed = json.loads(reading)
+
+    assert isinstance(parsed, dict)
+
+
+def test_required_fields_present():
+    sensor = CO2Sensor("Room101")
+    reading = json.loads(sensor.generate_co2_reading())
+
+    required_fields = ["sensor_type", "room", "value", "unit", "timestamp"]
+
+    for field in required_fields:
+        assert field in reading
+
+
+def test_co2_value_range():
+    sensor = CO2Sensor("Room101")
+
+    for _ in range(10):
+        reading = json.loads(sensor.generate_co2_reading())
+        value = reading["value"]
+
+        assert 400 <= value <= 1500
+
+
+def test_co2_drift_limit():
+    sensor = CO2Sensor("Room101")
+
+    first = json.loads(sensor.generate_co2_reading())["value"]
+    second = json.loads(sensor.generate_co2_reading())["value"]
+
+    drift = abs(second - first)
+
+    assert drift <= 50
\ No newline at end of file
diff --git a/tests/test_noise_sensor.py b/tests/test_noise_sensor.py
index e69de29..637c3ea 100644
--- a/tests/test_noise_sensor.py
+++ b/tests/test_noise_sensor.py
@@ -0,0 +1,47 @@
+import sys
+import os
+import json
+
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+from sensors.noise_sensor import NoiseSensor
+
+
+def test_generate_reading_returns_valid_json():
+    sensor = NoiseSensor("Room101")
+    reading = sensor.generate_noise_reading()
+
+    parsed = json.loads(reading)
+
+    assert isinstance(parsed, dict)
+
+
+def test_required_fields_present():
+    sensor = NoiseSensor("Room101")
+    reading = json.loads(sensor.generate_noise_reading())
+
+    required_fields = ["sensor_type", "room", "value", "unit", "timestamp"]
+
+    for field in required_fields:
+        assert field in reading
+
+
+def test_noise_value_range():
+    sensor = NoiseSensor("Room101")
+
+    for _ in range(10):
+        reading = json.loads(sensor.generate_noise_reading())
+        value = reading["value"]
+
+        assert 30 <= value <= 100
+
+
+def test_noise_drift_limit():
+    sensor = NoiseSensor("Room101")
+
+    first = json.loads(sensor.generate_noise_reading())["value"]
+    second = json.loads(sensor.generate_noise_reading())["value"]
+
+    drift = abs(second - first)
+
+    assert drift <= 5
\ No newline at end of file
diff --git a/tests/test_occupancy_sensor.py b/tests/test_occupancy_sensor.py
index e69de29..dfff44d 100644
--- a/tests/test_occupancy_sensor.py
+++ b/tests/test_occupancy_sensor.py
@@ -0,0 +1,48 @@
+import sys
+import os
+import json
+
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+from sensors.occupancy_sensor import OccupancySensor
+
+
+def test_generate_reading_returns_valid_json():
+    sensor = OccupancySensor("Room101", 40)
+    reading = sensor.generate_occupancy_reading()
+
+    parsed = json.loads(reading)
+
+    assert isinstance(parsed, dict)
+
+
+def test_required_fields_present():
+    sensor = OccupancySensor("Room101", 40)
+    reading = json.loads(sensor.generate_occupancy_reading())
+
+    required_fields = ["sensor_type", "room", "value", "unit", "timestamp"]
+
+    for field in required_fields:
+        assert field in reading
+
+
+def test_occupancy_value_range():
+    capacity = 40
+    sensor = OccupancySensor("Room101", capacity)
+
+    for _ in range(10):
+        reading = json.loads(sensor.generate_occupancy_reading())
+        value = reading["value"]
+
+        assert 0 <= value <= capacity
+
+
+def test_occupancy_drift_limit():
+    sensor = OccupancySensor("Room101", 40)
+
+    first = json.loads(sensor.generate_occupancy_reading())["value"]
+    second = json.loads(sensor.generate_occupancy_reading())["value"]
+
+    drift = abs(second - first)
+
+    assert drift <= 3
\ No newline at end of file
diff --git a/tests/test_temperature_sensor.py b/tests/test_temperature_sensor.py
index e69de29..5ec2922 100644
--- a/tests/test_temperature_sensor.py
+++ b/tests/test_temperature_sensor.py
@@ -0,0 +1,47 @@
+import sys
+import os
+import json
+
+sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
+
+from sensors.temperature_sensor import TemperatureSensor
+
+
+def test_generate_reading_returns_valid_json():
+    sensor = TemperatureSensor("Room101")
+    reading = sensor.generate_temperature_reading()
+
+    parsed = json.loads(reading)
+
+    assert isinstance(parsed, dict)
+
+
+def test_required_fields_present():
+    sensor = TemperatureSensor("Room101")
+    reading = json.loads(sensor.generate_temperature_reading())
+
+    required_fields = ["sensor_type", "room", "value", "unit", "timestamp"]
+
+    for field in required_fields:
+        assert field in reading
+
+
+def test_temperature_value_range():
+    sensor = TemperatureSensor("Room101")
+
+    for _ in range(10):
+        reading = json.loads(sensor.generate_temperature_reading())
+        value = reading["value"]
+
+        assert 18 <= value <= 30
+
+
+def test_temperature_drift_limit():
+    sensor = TemperatureSensor("Room101")
+
+    first = json.loads(sensor.generate_temperature_reading())["value"]
+    second = json.loads(sensor.generate_temperature_reading())["value"]
+
+    drift = abs(second - first)
+
+    assert drift <= 1
\ No newline at end of file