import numpy as np

from skimage.io._plugins._histograms import histograms


class TestHistogram:
    def test_basic(self):
        img = np.ones((50, 50, 3), dtype=np.uint8)
        bands = histograms(img, 255)
        for band in bands:
            np.testing.assert_equal(band.sum(), 50**2)

    def test_counts(self):
        channel = np.arange(255).reshape(51, 5)
        img = np.empty((51, 5, 3), dtype='uint8')
        img[:, :, 0] = channel
        img[:, :, 1] = channel
        img[:, :, 2] = channel
        r, g, b, v = histograms(img, 255)
        np.testing.assert_array_equal(r, g)
        np.testing.assert_array_equal(r, b)
        np.testing.assert_array_equal(r, v)
        np.testing.assert_array_equal(r, np.ones(255))