def test_dt_output_range(dummy_titanic):
    X_train, y_train, X_test, y_test = dummy_titanic
    dt = DecisionTree()
    dt.fit(X_train, y_train)
    pred_train = dt.predict(X_train)
    pred_test = dt.predict(X_test)

    assert (pred_train <= 1).all() & (pred_train >= 0).all(), 'Decision tree output should range from 0 to 1 inclusive'
    assert (pred_test <= 1).all() & (pred_test >= 0).all(), 'Decision tree output should range from 0 to 1 inclusive'