CanvasSpec.hs

module CanvasSpec where

import Test.Hspec
import Canvas
import Color

spec :: Spec
spec = describe "Canvas" $ do

    describe "Creating a Canvas" $ do
        let c = createCanvas 10 20
        it "c.width == 10" $
          width c `shouldBe` 10
        it "c.height == 20" $
          height c `shouldBe` 20
        it "every pixel of c is Color(0,0,0)" $
          True `shouldBe` all (Color (0,0,0) ==) (allPixels c)

    describe "Writing a pixel to a canvas" $ do
        let c = createCanvas 10 20
        let colorRed = Color (1, 0, 0)
        let c' = writePixelAt c 2 3 colorRed
        it "pixel 2,3 of c == colorRed" $
          pixelAt c' 2 3 == colorRed

    describe "Constructing the PPM header" $ do
        let c = createCanvas 5 3
        let ppm = ppmFromCanvas c
        it "lines 1-3 of ppm are [P3, 5 3, 255]" $
          unlines (take 3 (lines ppm)) `shouldBe` "P3\n5 3\n255\n"

    describe "Constructing the PPM pixel data" $ do
        let c = createCanvas 5 3
        let c1 = Color (1.5, 0, 0)
        let c2 = Color (0, 0.5, 0)
        let c3 = Color (-0.5, 0, 1)
        let c' = writePixelAt (writePixelAt (writePixelAt c 0 0 c1) 2 1 c2) 4 2 c3
        it "Lines 4-6 of PPM are \n\
\ 255 0 0 0 0 0 0 0 0 0 0 0 0 0 0 \n\
\ 0 0 0 0 0 0 0 128 0 0 0 0 0 0 0 \n\
\ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 255"  $
            unlines (drop 3 (lines(ppmFromCanvas c'))) `shouldBe` "255 0 0 0 0 0 0 0 0 0 0 0 0 0 0\n" ++
            "0 0 0 0 0 0 0 128 0 0 0 0 0 0 0\n" ++  "0 0 0 0 0 0 0 0 0 0 0 0 0 0 255\n"

    describe "Splitting long lines in PPM files" $ do
        let col = Color(1, 0.8, 0.6)
        let c = setAllPixelsTo (createCanvas 10 2) col
        let ppm = ppmFromCanvas c
        -- it "lines 4-7 of ppm are xxx" $
        --   unlines (take 3 (drop 3 (lines ppm))) `shouldBe` "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153\n" ++ 
        --   "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204 153\n"
        -- Replacing this test ^^ with a check of length for every line
        it "no line is longer than 70 characters" $
            all (\x -> length x <=70) (lines ppm) 
    
    describe "PPM files are terminated by a newline" $ do
        let c = createCanvas 5 3
        let ppm = ppmFromCanvas c
        it "the last character of ppm is a newline" $
          last ppm `shouldBe` '\n'