Add tests

bin/ODiffBin.re

@@ -21,7 +21,7 @@ let main =
       </Pastel>,
     );
 
-    Images.Rgba32(diff) |> Png.save(diffPath, []);
+    Odiff.ImageIO.saveImage(diffPath, diff)
     exit(1);
   } else {
     Console.log(

package.json

@@ -12,7 +12,8 @@
     "buildEnv": { "ODOC_SYNTAX": "re" }
   },
   "scripts": {
-    "test": "esy x ODiffBin",
+    "run": "esy x ODiffBin",
+    "test": "esy x RunTests.exe",
     "format": "esy dune build @fmt --auto-promote",
     "doc": "esy dune build @doc"
   },

src/Diff.re

@@ -9,9 +9,12 @@ let redPixel: Rgba32.elt = {
   },
 };
 
+let maxYIQPossibleDelta = 35215.
+
 let compare = (a, b, diff, ~threshold=0.1, ()) => {
   let diffCount = ref(0);
   let (base, comp) = calcSize(a) > calcSize(b) ? (a, b) : (b, a);
+  let maxDelta = maxYIQPossibleDelta *. threshold *. threshold
 
   for (x in 0 to base.width - 1) {
     for (y in 0 to base.height - 1) {
@@ -21,11 +24,11 @@ let compare = (a, b, diff, ~threshold=0.1, ()) => {
       if (r != r1 || g != g1 || b != b1 || a != a1) {
         let delta =
           ColorDelta.calculatePixelColorDelta(
-            (r, b, g, a),
-            (r1, b1, g1, a1),
+            (r, g, b, a),
+            (r1, g1, b1, a1),
           );
 
-        if (delta > threshold) {
+        if (delta > maxDelta) {
           diffCount := diffCount^ + 1;
           Rgba32.set(diff, x, y, redPixel);
         };

src/ImageIO.re

@@ -11,6 +11,9 @@ let loadImage = filename => {
   };
 };
 
+let saveImage = (filename, imageBuffer) =>
+  Images.Rgba32(imageBuffer) |> Png.save(filename, []);
+
 let readImgColor = (x, y, img) => {
   let (bytes, position) = Rgba32.unsafe_access(img, x, y);
 

test/PngTests.re

@@ -0,0 +1,42 @@
+open TestFramework;
+
+describe("Png comparing", ({test, _}) => {
+  test("finds different between 2 images", ({expect, _}) => {
+    let img1 = Odiff.ImageIO.loadImage("test/test-images/orange.png");
+    let img2 = Odiff.ImageIO.loadImage("test/test-images/orange_changed.png");
+
+    let diffOutput = Rgba32.copy(img1);
+
+    let diffPixels = Odiff.Diff.compare(img1, img2, diffOutput, ());
+    expect.int(diffPixels).toBe(1430);
+  });
+
+  test("uses provided threshold", ({expect, _}) => {
+    let img1 = Odiff.ImageIO.loadImage("test/test-images/orange.png");
+    let img2 = Odiff.ImageIO.loadImage("test/test-images/orange_changed.png");
+
+    let diffOutput = Rgba32.copy(img1);
+
+    let diffPixels =
+      Odiff.Diff.compare(img1, img2, diffOutput, ~threshold=1.0, ());
+    expect.int(diffPixels).toBe(184);
+  });
+
+  test("create right diff mask", ({expect, _}) => {
+    let img1 = Odiff.ImageIO.loadImage("test/test-images/orange.png");
+    let img2 = Odiff.ImageIO.loadImage("test/test-images/orange_changed.png");
+
+    let diffOutput = Rgba32.create(img1.width, img1.height);
+    Odiff.Diff.compare(img1, img2, diffOutput, ()) |> ignore;
+
+    let originalDiff =
+      Odiff.ImageIO.loadImage("test/test-images/orange-diff.png");
+    let diffMaskOfDiff =
+      Rgba32.create(originalDiff.width, originalDiff.height);
+
+    let diffOfDiffPixels =
+      Odiff.Diff.compare(originalDiff, diffOutput, diffMaskOfDiff, ());
+
+    expect.int(diffOfDiffPixels).toBe(0);
+  });
+});

test/RunTests.re

@@ -0,0 +1 @@
+OdiffTests.TestFramework.cli()

test/TestFramework.re

@@ -0,0 +1,7 @@
+include Rely.Make({
+  let config =
+    Rely.TestFrameworkConfig.initialize({
+      snapshotDir: "test/__snapshots__",
+      projectDir: "."
+    });
+});

test/dune

@@ -0,0 +1,21 @@
+(library
+   (name OdiffTests)
+   ; the linkall flag ensures that all of our tests are compiled and the
+   ; -g flag emits debugging information
+   (ocamlopt_flags -linkall -g)
+   ; you will want to depend on the library you are testing as well, however for
+   ; the purposes of this example we are only depending on the test runner itself
+   (libraries rely.lib odiff)
+   (modules (:standard \ RunTests))
+)
+(executable
+  ; the for the library is automatically detected because of the name, but we
+  ; need to explicitly specify the package here
+  (package odiff)
+  (name RunTests)
+  (public_name RunTests.exe)
+  (libraries
+    OdiffTests
+  )
+  (modules RunTests)
+)