Unidata / MetPy

    parcel_prof = parcel_profile(p, temperature[0], dewpoint[0]).to('degC')

    cape, cin = cape_cin(p, temperature, dewpoint, parcel_prof)

    assert_almost_equal(cape, 0.0 * units('joule / kilogram'), 6)

    assert_almost_equal(cin, 0.0 * units('joule / kilogram'), 6)

def test_find_append_zero_crossings():

    """Tests finding and appending zero crossings of an x, y series."""

    x = np.arange(11) * units.hPa

    y = np.array([3, 2, 1, -1, 2, 2, 0, 1, 0, -1, 2]) * units.degC

    x2, y2 = _find_append_zero_crossings(x, y)

    x_truth = np.array([0., 1., 2., 2.5, 3., 3.33333333, 4., 5.,

                        6., 7., 8., 9., 9.33333333, 10.]) * units.hPa

    y_truth = np.array([3, 2, 1, 0, -1, 0, 2, 2, 0, 1, 0, -1, 0, 2]) * units.degC

    temperature = np.array([22.2, 14.6, 12., 9.4, 7., -38.]) * units.celsius

    dewpoint = np.array([19., -11.2, -10.8, -10.4, -10., -53.2]) * units.celsius

    parcel_prof = parcel_profile(p, temperature[0], dewpoint[0])

    cape, cin = cape_cin(p, temperature, dewpoint, parcel_prof)

    assert_almost_equal(cape, 58.0368212 * units('joule / kilogram'), 6)

    assert_almost_equal(cin, -89.8073512 * units('joule / kilogram'), 6)

def test_cape_cin_no_el():

    """Tests that CAPE works with no EL."""

    p = np.array([959., 779.2, 751.3, 724.3]) * units.mbar

    temperature = np.array([22.2, 14.6, 12., 9.4]) * units.celsius

    dewpoint = np.array([19., -11.2, -10.8, -10.4]) * units.celsius

    parcel_prof = parcel_profile(p, temperature[0], dewpoint[0]).to('degC')

    cape, cin = cape_cin(p, temperature, dewpoint, parcel_prof)

    """Test LCL calculation convergence failure."""

    with pytest.raises(RuntimeError):

        lcl(1000. * units.mbar, 30. * units.degC, 20. * units.degC, max_iters=2)

def test_lfc_basic():

    """Test LFC calculation."""

    levels = np.array([959., 779.2, 751.3, 724.3, 700., 269.]) * units.mbar

    temperatures = np.array([22.2, 14.6, 12., 9.4, 7., -49.]) * units.celsius

    dewpoints = np.array([19., -11.2, -10.8, -10.4, -10., -53.2]) * units.celsius

    l = lfc(levels, temperatures, dewpoints)

    assert_almost_equal(l[0], 727.468 * units.mbar, 2)

    assert_almost_equal(l[1], 9.705 * units.celsius, 2)

    assert_almost_equal(rh, 81.7219 * units.percent, 3)

def test_mixing_ratio_from_specific_humidity():

    """Tests mixing ratio from specific humidity."""

    q = 0.012

    w = mixing_ratio_from_specific_humidity(q)

    assert_almost_equal(w, 0.01215, 3)

def test_rh_specific_humidity():

    """Tests relative humidity from specific humidity."""

    p = 1013.25 * units.mbar

    temperature = 20. * units.degC

    q = 0.012