"""Test homeassistant volume utility functions."""

import unittest
import homeassistant.util.volume as volume_util
from homeassistant.const import (VOLUME_LITERS, VOLUME_MILLILITERS,
                                 VOLUME_GALLONS, VOLUME_FLUID_OUNCE)
import pytest

INVALID_SYMBOL = 'bob'
VALID_SYMBOL = VOLUME_LITERS


class TestVolumeUtil(unittest.TestCase):
    """Test the volume utility functions."""

    def test_convert_same_unit(self):
        """Test conversion from any unit to same unit."""
        assert 2 == volume_util.convert(2, VOLUME_LITERS, VOLUME_LITERS)
        assert 3 == volume_util.convert(3, VOLUME_MILLILITERS,
                                        VOLUME_MILLILITERS)
        assert 4 == volume_util.convert(4, VOLUME_GALLONS,
                                        VOLUME_GALLONS)
        assert 5 == volume_util.convert(5, VOLUME_FLUID_OUNCE,
                                        VOLUME_FLUID_OUNCE)

    def test_convert_invalid_unit(self):
        """Test exception is thrown for invalid units."""
        with pytest.raises(ValueError):
            volume_util.convert(5, INVALID_SYMBOL, VALID_SYMBOL)

        with pytest.raises(ValueError):
            volume_util.convert(5, VALID_SYMBOL, INVALID_SYMBOL)

    def test_convert_nonnumeric_value(self):
        """Test exception is thrown for nonnumeric type."""
        with pytest.raises(TypeError):
            volume_util.convert('a', VOLUME_GALLONS, VOLUME_LITERS)

    def test_convert_from_liters(self):
        """Test conversion from liters to other units."""
        liters = 5
        assert volume_util.convert(liters, VOLUME_LITERS,
                                   VOLUME_GALLONS) == 1.321

    def test_convert_from_gallons(self):
        """Test conversion from gallons to other units."""
        gallons = 5
        assert volume_util.convert(gallons, VOLUME_GALLONS,
                                   VOLUME_LITERS) == 18.925