test_units.py

from datetime import datetime
import platform
from unittest.mock import MagicMock

import matplotlib.pyplot as plt
from matplotlib.testing.decorators import check_figures_equal, image_comparison
import matplotlib.units as munits
import numpy as np
import pytest


# Basic class that wraps numpy array and has units
class Quantity:
    def __init__(self, data, units):
        self.magnitude = data
        self.units = units

    def to(self, new_units):
        factors = {('hours', 'seconds'): 3600, ('minutes', 'hours'): 1 / 60,
                   ('minutes', 'seconds'): 60, ('feet', 'miles'): 1 / 5280.,
                   ('feet', 'inches'): 12, ('miles', 'inches'): 12 * 5280}
        if self.units != new_units:
            mult = factors[self.units, new_units]
            return Quantity(mult * self.magnitude, new_units)
        else:
            return Quantity(self.magnitude, self.units)

    def __getattr__(self, attr):
        return getattr(self.magnitude, attr)

    def __getitem__(self, item):
        if np.iterable(self.magnitude):
            return Quantity(self.magnitude[item], self.units)
        else:
            return Quantity(self.magnitude, self.units)

    def __array__(self):
        return np.asarray(self.magnitude)


@pytest.fixture
def quantity_converter():
    # Create an instance of the conversion interface and
    # mock so we can check methods called
    qc = munits.ConversionInterface()

    def convert(value, unit, axis):
        if hasattr(value, 'units'):
            return value.to(unit).magnitude
        elif np.iterable(value):
            try:
                return [v.to(unit).magnitude for v in value]
            except AttributeError:
                return [Quantity(v, axis.get_units()).to(unit).magnitude
                        for v in value]
        else:
            return Quantity(value, axis.get_units()).to(unit).magnitude

    def default_units(value, axis):
        if hasattr(value, 'units'):
            return value.units
        elif np.iterable(value):
            for v in value:
                if hasattr(v, 'units'):
                    return v.units
            return None

    qc.convert = MagicMock(side_effect=convert)
    qc.axisinfo = MagicMock(side_effect=lambda u, a: munits.AxisInfo(label=u))
    qc.default_units = MagicMock(side_effect=default_units)
    return qc


# Tests that the conversion machinery works properly for classes that
# work as a facade over numpy arrays (like pint)
@image_comparison(['plot_pint.png'], remove_text=False, style='mpl20',
                  tol={'aarch64': 0.02}.get(platform.machine(), 0.0))
def test_numpy_facade(quantity_converter):
    # use former defaults to match existing baseline image
    plt.rcParams['axes.formatter.limits'] = -7, 7

    # Register the class
    munits.registry[Quantity] = quantity_converter

    # Simple test
    y = Quantity(np.linspace(0, 30), 'miles')
    x = Quantity(np.linspace(0, 5), 'hours')

    fig, ax = plt.subplots()
    fig.subplots_adjust(left=0.15)  # Make space for label
    ax.plot(x, y, 'tab:blue')
    ax.axhline(Quantity(26400, 'feet'), color='tab:red')
    ax.axvline(Quantity(120, 'minutes'), color='tab:green')
    ax.yaxis.set_units('inches')
    ax.xaxis.set_units('seconds')

    assert quantity_converter.convert.called
    assert quantity_converter.axisinfo.called
    assert quantity_converter.default_units.called


# Tests gh-8908
@image_comparison(['plot_masked_units.png'], remove_text=True, style='mpl20',
                  tol={'aarch64': 0.02}.get(platform.machine(), 0.0))
def test_plot_masked_units():
    data = np.linspace(-5, 5)
    data_masked = np.ma.array(data, mask=(data > -2) & (data < 2))
    data_masked_units = Quantity(data_masked, 'meters')

    fig, ax = plt.subplots()
    ax.plot(data_masked_units)


def test_empty_set_limits_with_units(quantity_converter):
    # Register the class
    munits.registry[Quantity] = quantity_converter

    fig, ax = plt.subplots()
    ax.set_xlim(Quantity(-1, 'meters'), Quantity(6, 'meters'))
    ax.set_ylim(Quantity(-1, 'hours'), Quantity(16, 'hours'))


@image_comparison(['jpl_bar_units.png'],
                  savefig_kwarg={'dpi': 120}, style='mpl20')
def test_jpl_bar_units():
    import matplotlib.testing.jpl_units as units
    units.register()

    day = units.Duration("ET", 24.0 * 60.0 * 60.0)
    x = [0*units.km, 1*units.km, 2*units.km]
    w = [1*day, 2*day, 3*day]
    b = units.Epoch("ET", dt=datetime(2009, 4, 25))

    fig, ax = plt.subplots()
    ax.bar(x, w, bottom=b)
    ax.set_ylim([b-1*day, b+w[-1]+1*day])


@image_comparison(['jpl_barh_units.png'],
                  savefig_kwarg={'dpi': 120}, style='mpl20')
def test_jpl_barh_units():
    import matplotlib.testing.jpl_units as units
    units.register()

    day = units.Duration("ET", 24.0 * 60.0 * 60.0)
    x = [0*units.km, 1*units.km, 2*units.km]
    w = [1*day, 2*day, 3*day]
    b = units.Epoch("ET", dt=datetime(2009, 4, 25))

    fig, ax = plt.subplots()
    ax.barh(x, w, left=b)
    ax.set_xlim([b-1*day, b+w[-1]+1*day])


def test_empty_arrays():
    # Check that plotting an empty array with a dtype works
    plt.scatter(np.array([], dtype='datetime64[ns]'), np.array([]))


def test_scatter_element0_masked():

    times = np.arange('2005-02', '2005-03', dtype='datetime64[D]')

    y = np.arange(len(times), dtype='float')
    y[0] = np.nan
    fig, ax = plt.subplots()
    ax.scatter(times, y)
    fig.canvas.draw()


@check_figures_equal(extensions=["png"])
def test_subclass(fig_test, fig_ref):
    class subdate(datetime):
        pass

    fig_test.subplots().plot(subdate(2000, 1, 1), 0, "o")
    fig_ref.subplots().plot(datetime(2000, 1, 1), 0, "o")