"""Test homeassistant pressure utility functions."""
import pytest

from homeassistant.const import (PRESSURE_PA, PRESSURE_HPA, PRESSURE_MBAR,
                                 PRESSURE_INHG, PRESSURE_PSI)
import homeassistant.util.pressure as pressure_util

INVALID_SYMBOL = 'bob'
VALID_SYMBOL = PRESSURE_PA


def test_convert_same_unit():
    """Test conversion from any unit to same unit."""
    assert pressure_util.convert(2, PRESSURE_PA, PRESSURE_PA) == 2
    assert pressure_util.convert(3, PRESSURE_HPA, PRESSURE_HPA) == 3
    assert pressure_util.convert(4, PRESSURE_MBAR, PRESSURE_MBAR) == 4
    assert pressure_util.convert(5, PRESSURE_INHG, PRESSURE_INHG) == 5


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

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


def test_convert_nonnumeric_value():
    """Test exception is thrown for nonnumeric type."""
    with pytest.raises(TypeError):
        pressure_util.convert('a', PRESSURE_HPA, PRESSURE_INHG)


def test_convert_from_hpascals():
    """Test conversion from hPA to other units."""
    hpascals = 1000
    assert pressure_util.convert(hpascals, PRESSURE_HPA, PRESSURE_PSI) == \
        pytest.approx(14.5037743897)
    assert pressure_util.convert(hpascals, PRESSURE_HPA, PRESSURE_INHG) == \
        pytest.approx(29.5299801647)
    assert pressure_util.convert(hpascals, PRESSURE_HPA, PRESSURE_PA) == \
        pytest.approx(100000)
    assert pressure_util.convert(hpascals, PRESSURE_HPA, PRESSURE_MBAR) == \
        pytest.approx(1000)


def test_convert_from_inhg():
    """Test conversion from inHg to other units."""
    inhg = 30
    assert pressure_util.convert(inhg, PRESSURE_INHG, PRESSURE_PSI) == \
        pytest.approx(14.7346266155)
    assert pressure_util.convert(inhg, PRESSURE_INHG, PRESSURE_HPA) == \
        pytest.approx(1015.9167)
    assert pressure_util.convert(inhg, PRESSURE_INHG, PRESSURE_PA) == \
        pytest.approx(101591.67)
    assert pressure_util.convert(inhg, PRESSURE_INHG, PRESSURE_MBAR) == \
        pytest.approx(1015.9167)