#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Import modules
import pytest
import numpy as np

# Import from pyswarms
from pyswarms.discrete import BinaryPSO
from pyswarms.utils.functions.single_obj import sphere

from .abc_test_discrete_optimizer import ABCTestDiscreteOptimizer


class TestDiscreteOptimizer(ABCTestDiscreteOptimizer):
    @pytest.fixture
    def optimizer(self):
        return BinaryPSO

    @pytest.fixture
    def optimizer_history(self, options):
        opt = BinaryPSO(10, 2, options=options)
        opt.optimize(sphere, 1000)
        return opt

    @pytest.fixture
    def optimizer_reset(self, options):
        opt = BinaryPSO(10, 2, options=options)
        opt.optimize(sphere, 10)
        opt.reset()
        return opt

    def test_binary_correct_pos(self, options):
        """Test to check binary optimiser returns the correct position
        corresponding to the best cost"""
        opt = BinaryPSO(10, 2, options=options)
        cost, pos = opt.optimize(sphere, 10)
        # find best pos from history
        min_cost_idx = np.argmin(opt.cost_history)
        min_pos_idx = np.argmin(sphere(opt.pos_history[min_cost_idx]))
        assert np.array_equal(opt.pos_history[min_cost_idx][min_pos_idx], pos)