df_test = pd.read_csv('HR_test.csv')
X1 = df_test[['col1', 'col2']] # Must be the same columns as the training data otherwise it wont work. If you want to experiment with different columns always change the training ones first and then those here.
y1 = df_test['left']

# Scoring
model.score(X1, y1) # Make sure you use the testing data, not training (X_test, y_test)