test_wordcloud.py

from wordcloud import WordCloud
import numpy as np
from nose.tools import assert_equal, assert_greater, assert_true, assert_raises
from numpy.testing import assert_array_equal
from PIL import Image

from tempfile import NamedTemporaryFile

THIS = """The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!
"""


def test_default():
    # test that default word cloud creation and conversions work
    wc = WordCloud(max_words=50)
    wc.generate(THIS)

    # check for proper word extraction
    assert_equal(len(wc.words_), wc.max_words)

    # check that we got enough words
    assert_equal(len(wc.layout_), wc.max_words)

    # check image export
    wc_image = wc.to_image()
    assert_equal(wc_image.size, (wc.width, wc.height))

    # check that numpy conversion works
    wc_array = np.array(wc)
    assert_array_equal(wc_array, wc.to_array())

    # check size
    assert_equal(wc_array.shape, (wc.height, wc.width, 3))


def test_writing_to_file():
    wc = WordCloud()
    wc.generate(THIS)
    # check writing to file
    f = NamedTemporaryFile(suffix=".png")
    filename = f.name
    wc.to_file(filename)
    loaded_image = Image.open(filename)
    assert_equal(loaded_image.size, (wc.width, wc.height))


def test_check_errors():
    wc = WordCloud()
    assert_raises(NotImplementedError, wc.to_html)

    try:
        np.array(wc)
        raise AssertionError("np.array(wc) didn't raise")
    except ValueError as e:
        assert_true("call generate" in str(e))

    try:
        wc.recolor()
        raise AssertionError("wc.recolor didn't raise")
    except ValueError as e:
        assert_true("call generate" in str(e))


def test_recolor():
    wc = WordCloud(max_words=50)
    wc.generate(THIS)
    array_before = wc.to_array()
    wc.recolor()
    array_after = wc.to_array()
    # check that the same places are filled
    assert_array_equal(array_before.sum(axis=-1) != 0,
                       array_after.sum(axis=-1) != 0)
    # check that they are not the same
    assert_greater(np.abs(array_before - array_after).sum(), 10000)

    # check that recoloring is deterministic
    wc.recolor(random_state=10)
    wc_again = wc.to_array()
    assert_array_equal(wc_again, wc.recolor(random_state=10))


def test_random_state():
    # check that random state makes everything deterministic
    wc = WordCloud(random_state=0)
    wc2 = WordCloud(random_state=0)
    wc.generate(THIS)
    wc2.generate(THIS)
    assert_array_equal(wc, wc2)


def test_mask():
    # test masks

    # check that using an empty mask is equivalent to not using a mask
    wc = WordCloud(random_state=42)
    wc.generate(THIS)
    mask = np.zeros(np.array(wc).shape[:2])
    wc_mask = WordCloud(mask=mask, random_state=42)
    wc_mask.generate(THIS)
    assert_array_equal(wc, wc_mask)

    # use actual nonzero mask
    mask = np.zeros((234, 456))
    mask[100:150, 300:400] = 1

    wc = WordCloud(mask=mask)
    wc.generate(THIS)
    wc_array = np.array(wc)
    assert_equal(mask.shape, wc_array.shape[:2])
    assert_array_equal(wc_array[mask != 0], 0)
    assert_greater(wc_array[mask == 0].sum(), 10000)


def check_parameters():
    # check that parameters are actually used
    pass