diff --git a/src/main/java/PasswordHasher.java b/src/main/java/PasswordHasher.java
index 14a1137..2ae5d8d 100644
--- a/src/main/java/PasswordHasher.java
+++ b/src/main/java/PasswordHasher.java
@@ -3,6 +3,10 @@ import java.security.NoSuchAlgorithmException;
 
 public class PasswordHasher {
     public static String hashPassword(String password) {
+    	if (password == null) {
+            throw new IllegalArgumentException("Password cannot be null");
+        }
+    	
         try {
             MessageDigest digest = MessageDigest.getInstance("SHA-256");
             byte[] hash = digest.digest(password.getBytes());
diff --git a/src/test/java/PasswordHasherTest.java b/src/test/java/PasswordHasherTest.java
new file mode 100644
index 0000000..6177642
--- /dev/null
+++ b/src/test/java/PasswordHasherTest.java
@@ -0,0 +1,27 @@
+import org.junit.jupiter.api.Test;
+
+import static org.junit.Assert.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+public class PasswordHasherTest {
+
+	@Test
+    void testHashPassword() {
+        String password = "password123";
+        String hashedPassword = PasswordHasher.hashPassword(password);
+
+        // Check that the hashed password is not null
+        assertEquals(64, hashedPassword.length());
+
+        // Test with an empty password
+        String emptyPassword = "";
+        String hashedEmptyPassword = PasswordHasher.hashPassword(emptyPassword);
+        assertEquals(64, hashedEmptyPassword.length());
+
+        // Test with a null password
+        assertThrows(IllegalArgumentException.class, () -> {
+            PasswordHasher.hashPassword(null);
+        });
+    }
+}
\ No newline at end of file
diff --git a/user.json b/user.json
index 8242745..c44dc44 100644
--- a/user.json
+++ b/user.json
@@ -1,29 +1,3 @@
 [
-  {
-    "id": "c99b1061-13b7-4fa8-b1ac-814e07db3ef4",
-    "userName": "Test",
-    "password": "8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92",
-    "birthday": "",
-    "firstName": "",
-    "surname": "",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "89de267d-8456-4393-9fab-a5ddb36c7686",
-    "userName": "existinguser",
-    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
-    "birthday": "1990-01-01",
-    "firstName": "John",
-    "surname": "Doe",
-    "stayLoggedIn": false
-  },
-  {
-    "id": "43d45e81-3540-427f-8cb9-8f279d7a18d3",
-    "userName": "testUser",
-    "password": "5e884898da28047151d0e56f8dc6292773603d0d6aabbdd62a11ef721d1542d8",
-    "birthday": "1990-01-01",
-    "firstName": "John",
-    "surname": "Doe",
-    "stayLoggedIn": false
-  }
+
 ]
\ No newline at end of file