How to mock function on unit test actix web

Question

I have an api service that has 2 layer: api and repository. The api layer is where the request handling and business logic defined, while repository is a database call functions. I want to mock the database call function on the unit testing of my api layer, is there any way i can do it with actix web?

pub fn login(db: web::Data<Pool>, payload: Json<LoginInput>) -> Result<Token, Error> {

    // Function i want to mock:
    let user =
        match get_user_by_email(&db.get().unwrap(), payload.email.to_string()) {
            // This return status code of bad request
            Err(e) => return Error::InvalidUser,
            Ok(user) => user,
        };

    let user_claims = UserClaims {
        id: user.id,
        email: user.email
    };

    match verify(payload.password.to_string(), &user.password) {
        Err(e) => return Error::BadRequest(e),
        Ok(result) => match result {
            false => return Error::InvalidUser,
            _ => {}
        },
    };

    let token = generate_access_and_refresh_token(user_claims);

    token
}

The test:

#[actix_web::test]
async fn test_login() {
    let payload = create_mock_login_payload();
    let req = test::TestRequest::default()
        .set_json(payload)
        .to_http_request();

    let resp = login(req).await.unwrap();
    assert_eq!(resp.status(), StatusCode::BadRequest);
}

The mock function behavior that i want:

fn get_user_by_email(db: Pool, email: String) -> Result<User, Error> {
   if !email_valid(email) {
       return Err(Error::InvalidEmail);
   }
   Ok(create_mock_user())
}