from numpy.testing import assert_array_equal, assert_raises, run_module_suite
from skimage import data
from skimage.transform import pyramids


image = data.lena()
image_gray = image[..., 0]


def test_pyramid_reduce():
    # RGB image
    rows, cols, dim = image.shape
    out = pyramids.pyramid_reduce(image, downscale=2)
    assert_array_equal(out.shape, (rows / 2, cols / 2, dim))

    # grayscale image
    rows, cols = image_gray.shape
    out = pyramids.pyramid_reduce(image_gray, downscale=2)
    assert_array_equal(out.shape, (rows / 2, cols / 2))


def test_pyramid_expand():
    # RGB image
    rows, cols, dim = image.shape
    out = pyramids.pyramid_expand(image, upscale=2)
    assert_array_equal(out.shape, (rows * 2, cols * 2, dim))

    # grayscale image
    rows, cols = image_gray.shape
    out = pyramids.pyramid_expand(image_gray, upscale=2)
    assert_array_equal(out.shape, (rows * 2, cols * 2))


def test_build_gaussian_pyramid():
    # RGB image
    rows, cols, dim = image.shape
    pyramid = pyramids.pyramid_gaussian(image, downscale=2)
    for layer, out in enumerate(pyramid):
        layer_shape = (rows / 2 ** layer, cols / 2 ** layer, dim)
        assert_array_equal(out.shape, layer_shape)

    # grayscale image
    rows, cols = image_gray.shape
    pyramid = pyramids.pyramid_gaussian(image_gray, downscale=2)
    for layer, out in enumerate(pyramid):
        layer_shape = (rows / 2 ** layer, cols / 2 ** layer)
        assert_array_equal(out.shape, layer_shape)


def test_build_laplacian_pyramid():
    # RGB image
    rows, cols, dim = image.shape
    pyramid = pyramids.pyramid_laplacian(image, downscale=2)
    for layer, out in enumerate(pyramid):
        layer_shape = (rows / 2 ** layer, cols / 2 ** layer, dim)
        assert_array_equal(out.shape, layer_shape)

    # grayscale image
    rows, cols = image_gray.shape
    pyramid = pyramids.pyramid_laplacian(image_gray, downscale=2)
    for layer, out in enumerate(pyramid):
        layer_shape = (rows / 2 ** layer, cols / 2 ** layer)
        assert_array_equal(out.shape, layer_shape)


def test_check_factor():
    assert_raises(ValueError, pyramids._check_factor, 0.99)
    assert_raises(ValueError, pyramids._check_factor, - 2)


if __name__ == "__main__":
    run_module_suite()