diff --git a/src/file-processor/app/api/dependencies.py b/src/file-processor/app/api/dependencies.py
index cf930b9..e52a3de 100644
--- a/src/file-processor/app/api/dependencies.py
+++ b/src/file-processor/app/api/dependencies.py
@@ -79,7 +79,7 @@ def get_current_user(
   return user
 
 
-def get_admin_user(current_user: UserInDB = Depends(get_current_user)) -> UserInDB:
+def   get_admin_user(current_user: UserInDB = Depends(get_current_user)) -> UserInDB:
   """
   Dependency to ensure current user has admin role.
 
diff --git a/tests/api/test_users.py b/tests/api/test_users.py
new file mode 100644
index 0000000..8e359bf
--- /dev/null
+++ b/tests/api/test_users.py
@@ -0,0 +1,167 @@
+# File: tests/api/test_users.py
+from datetime import datetime
+from unittest.mock import MagicMock
+
+import pytest
+from fastapi import status
+from fastapi.testclient import TestClient
+
+from app.api.dependencies import get_admin_user, get_user_service
+from app.main import app
+from app.models.auth import UserRole
+from app.models.types import PyObjectId
+from app.models.user import UserInDB, UserCreate
+from app.services.user_service import UserService
+
+
+# -----------------------
+# Fixtures
+# -----------------------
+
+@pytest.fixture
+def fake_user_admin():
+  return UserInDB(
+    _id=PyObjectId(),
+    username="admin",
+    email="admin@example.com",
+    role=UserRole.ADMIN,
+    is_active=True,
+    hashed_password="hashed-secret",
+    created_at=datetime(2025, 1, 1),
+    updated_at=datetime(2025, 1, 2),
+  )
+
+
+@pytest.fixture
+def fake_user_response():
+  return UserInDB(
+    _id=PyObjectId(),
+    username="other",
+    email="other@example.com",
+    role=UserRole.USER,
+    is_active=True,
+    hashed_password="hashed-secret-2",
+    created_at=datetime(2025, 1, 1),
+    updated_at=datetime(2025, 1, 2),
+  )
+
+
+@pytest.fixture
+def client(fake_user_admin):
+  # Fake admin dependency
+  def get_admin_user_override():
+    return fake_user_admin
+  
+  # Fake user service
+  user_service_mock = MagicMock(spec=UserService)
+  
+  def get_user_service_override():
+    return user_service_mock
+  
+  client = TestClient(app)
+  client.app.dependency_overrides = {
+      get_admin_user: get_admin_user_override,
+      get_user_service: get_user_service_override
+  }
+  
+  client.user_service_mock = user_service_mock
+  return client
+
+
+# -----------------------
+# Tests
+# -----------------------
+
+class TestListUsers:
+  
+  def test_i_can_list_users(self, client, fake_user_admin, fake_user_response):
+    client.user_service_mock.list_users.return_value = [fake_user_admin, fake_user_response]
+    response = client.get("/users")
+    assert response.status_code == status.HTTP_200_OK
+    data = response.json()
+    assert len(data) == 2
+    assert data[0]["username"] == "admin"
+  
+  def test_i_can_list_users_when_empty(self, client):
+    client.user_service_mock.list_users.return_value = []
+    response = client.get("/users")
+    assert response.status_code == status.HTTP_200_OK
+    assert response.json() == []
+
+
+class TestGetUserById:
+  
+  def test_i_can_get_user_by_id(self, client, fake_user_response):
+    client.user_service_mock.get_user_by_id.return_value = fake_user_response
+    response = client.get(f"/users/{fake_user_response.id}")
+    assert response.status_code == status.HTTP_200_OK
+    data = response.json()
+    assert data["username"] == fake_user_response.username
+  
+  def test_i_cannot_get_user_by_id_not_found(self, client):
+    client.user_service_mock.get_user_by_id.return_value = None
+    response = client.get("/users/64f0c9f4b0d1c8b7b8e1f0a2")
+    assert response.status_code == status.HTTP_404_NOT_FOUND
+    assert response.json()["detail"] == "User not found"
+
+
+class TestCreateUser:
+  
+  def test_i_can_create_user(self, client, fake_user_response):
+    user_data = UserCreate(username="newuser",
+                           email="new@example.com",
+                           password="#Passw0rd!",
+                           role=UserRole.USER)
+    
+    client.user_service_mock.create_user.return_value = fake_user_response
+    response = client.post("/users", json=user_data.model_dump(mode="json"))
+    assert response.status_code == status.HTTP_201_CREATED
+    data = response.json()
+    assert data["username"] == fake_user_response.username
+  
+  def test_i_cannot_create_user_when_service_raises_value_error(self, client):
+    user_data = {"username": "baduser", "email": "bad@example.com", "role": "user", "password": "password"}
+    client.user_service_mock.create_user.side_effect = ValueError("Invalid data")
+    response = client.post("/users", json=user_data)
+    assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY
+
+
+class TestUpdateUser:
+  
+  def test_i_can_update_user(self, client, fake_user_response):
+    user_data = {"username": "updateduser", "email": "updated@example.com"}
+    client.user_service_mock.update_user.return_value = fake_user_response
+    response = client.put(f"/users/{fake_user_response.id}", json=user_data)
+    assert response.status_code == status.HTTP_200_OK
+    data = response.json()
+    assert data["username"] == fake_user_response.username
+  
+  def test_i_cannot_update_user_not_found(self, client):
+    client.user_service_mock.update_user.return_value = None
+    user_data = {"username": "updateduser"}
+    response = client.put("/users/64f0c9f4b0d1c8b7b8e1f0a2", json=user_data)
+    assert response.status_code == status.HTTP_404_NOT_FOUND
+    assert response.json()["detail"] == "User not found"
+  
+  def test_i_cannot_update_user_when_service_raises_value_error(self, client):
+    client.user_service_mock.update_user.side_effect = ValueError("Invalid update")
+    user_data = {"username": "badupdate"}
+    response = client.put("/users/64f0c9f4b0d1c8b7b8e1f0a2", json=user_data)
+    assert response.status_code == status.HTTP_400_BAD_REQUEST
+    assert response.json()["detail"] == "Invalid update"
+
+
+class TestDeleteUser:
+  
+  def test_i_can_delete_user(self, client):
+    client.user_service_mock.delete_user.return_value = True
+    response = client.delete("/users/64f0c9f4b0d1c8b7b8e1f0a1")
+    assert response.status_code == status.HTTP_200_OK
+    data = response.json()
+    assert data["message"] == "User successfully deleted"
+  
+  def test_i_cannot_delete_user_not_found(self, client):
+    client.user_service_mock.delete_user.return_value = False
+    response = client.delete("/users/64f0c9f4b0d1c8b7b8e1f0a2")
+    assert response.status_code == status.HTTP_404_NOT_FOUND
+    assert response.json()["detail"] == "User not found"