
using Color

# Test the colordiff function against example input and output from:
#
#   Sharma, G., Wu, W., & Dalal, E. N. (2005). The CIEDE2000 color‐difference
#   formula: Implementation notes, supplementary test data, and mathematical
#   observations. Color Research & Application, 30(1), 21–30. doi:10.1002/col
#

const abds = [
    ((50.0000,   2.6772, -79.7751), (50.0000,   0.0000, -82.7485),  2.0425),
    ((50.0000,   3.1571, -77.2803), (50.0000,   0.0000, -82.7485),  2.8615),
    ((50.0000,   2.8361, -74.0200), (50.0000,   0.0000, -82.7485),  3.4412),
    ((50.0000,  -1.3802, -84.2814), (50.0000,   0.0000, -82.7485),  1.0000),
    ((50.0000,  -1.1848, -84.8006), (50.0000,   0.0000, -82.7485),  1.0000),
    ((50.0000,  -0.9009, -85.5211), (50.0000,   0.0000, -82.7485),  1.0000),
    ((50.0000,   0.0000,   0.0000), (50.0000,  -1.0000,   2.0000),  2.3669),
    ((50.0000,  -1.0000,   2.0000), (50.0000,   0.0000,   0.0000),  2.3669),
    ((50.0000,   2.4900,  -0.0010), (50.0000,  -2.4900,   0.0009),  7.1792),
    ((50.0000,   2.4900,  -0.0010), (50.0000,  -2.4900,   0.0010),  7.1792),
    ((50.0000,   2.4900,  -0.0010), (50.0000,  -2.4900,   0.0011),  7.2195),
    ((50.0000,   2.4900,  -0.0010), (50.0000,  -2.4900,   0.0012),  7.2195),
    ((50.0000,  -0.0010,   2.4900), (50.0000,   0.0009,  -2.4900),  4.8045),
    ((50.0000,  -0.0010,   2.4900), (50.0000,   0.0010,  -2.4900),  4.8045),
    ((50.0000,  -0.0010,   2.4900), (50.0000,   0.0011,  -2.4900),  4.7461),
    ((50.0000,   2.5000,   0.0000), (50.0000,   0.0000,  -2.5000),  4.3065),
    ((50.0000,   2.5000,   0.0000), (73.0000,  25.0000, -18.0000), 27.1492),
    ((50.0000,   2.5000,   0.0000), (61.0000,  -5.0000,  29.0000), 22.8977),
    ((50.0000,   2.5000,   0.0000), (56.0000, -27.0000,  -3.0000), 31.9030),
    ((50.0000,   2.5000,   0.0000), (58.0000,  24.0000,  15.0000), 19.4535),
    ((50.0000,   2.5000,   0.0000), (50.0000,   3.1736,   0.5854),  1.0000),
    ((50.0000,   2.5000,   0.0000), (50.0000,   3.2972,   0.0000),  1.0000),
    ((50.0000,   2.5000,   0.0000), (50.0000,   1.8634,   0.5757),  1.0000),
    ((50.0000,   2.5000,   0.0000), (50.0000,   3.2592,   0.3350),  1.0000),
    ((60.2574, -34.0099,  36.2577), (60.4626, -34.1751,  39.4387),  1.2644),
    ((63.0109, -31.0961,  -5.8663), (62.8187, -29.7946,  -4.0864),  1.2530),
    ((61.2901,   3.7196,  -5.3901), (61.4292,   2.2480,  -4.9620),  1.8731),
    ((35.0831, -44.1164,   3.7933), (35.0232, -40.0716,   1.5901),  1.8645),
    ((22.7233,  20.0904, -46.6940), (23.0331,  14.9730, -42.5619),  2.0373),
    ((36.4612,  47.8580,  18.3852), (36.2715,  50.5065,  21.2231),  1.4146),
    ((90.8027,  -2.0831,   1.4410), (91.1528,  -1.6435,   0.0447),  1.4441),
    ((90.9257,  -0.5406,  -0.9208), (88.6381,  -0.8985,  -0.7239),  1.5381),
    (( 6.7747,  -0.2908,  -2.4247), ( 5.8714,  -0.0985,  -2.2286),  0.6377),
    ((2.0776,    0.0795,  -1.1350), ( 0.9033,  -0.0636,  -0.5514),  0.9082)]


const eps_cdiff = 0.01

metric = DE_2000()

for (i, (a, b, dexpect)) in enumerate(abds)
    @assert abs(dexpect - colordiff(Lab(a...), Lab(b...), metric)) < eps_cdiff
    @assert abs(dexpect - colordiff(Lab(b...), Lab(a...), metric)) < eps_cdiff
end
