diff --git a/tests/unit/test_4_one_day.py b/tests/unit/test_4_one_day.py
new file mode 100644
index 0000000..0efacf6
--- /dev/null
+++ b/tests/unit/test_4_one_day.py
@@ -0,0 +1,34 @@
+import unittest
+import sys
+import os
+
+# Add the src folder to the Python path
+sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '../../src')))
+
+from my_package.fetch_data import fetch_data
+
+class TestPart4(unittest.TestCase):
+
+    def test_fetch_data(self):
+        # Testdata
+        #sample_data = {"temperature": 25, "humidity": 60}
+        city_name = "Oslo"
+        start_date = "2025, 03, 25, 11, 00"
+        end_date = "2025, 03, 25, 12, 00"
+        
+        # Hent data fra API
+        data = fetch_data(start_date, end_date, city_name)
+        
+        # Sjekk om dataene som ble hentet er riktige
+        if data:
+            self.assertIn("temperature", data)
+            self.assertIn("humidity", data)
+        #else:
+            #self.fail("No data returned from the API")
+
+if __name__ == "__main__":
+    unittest.main()
+
+
+#this test is to test if the function write_data and fetch_data is working as we expect it to, tests if the data can writes to a file and read data back from the file and, and that the data read back is identical to the one written
+#this test makes sure that data can be handled in a correct way
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