From 1ae8e38ba4d9c141533a5a44e9fc1c470f4b29ff Mon Sep 17 00:00:00 2001
From: Nick White <git@njw.name>
Date: Thu, 23 Jul 2020 13:54:53 +0100
Subject: Add first test

---
 integralimg_test.go |  60 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 testdata/in.png     | Bin 0 -> 9123 bytes
 2 files changed, 60 insertions(+)
 create mode 100644 integralimg_test.go
 create mode 100644 testdata/in.png

diff --git a/integralimg_test.go b/integralimg_test.go
new file mode 100644
index 0000000..3bc8dd6
--- /dev/null
+++ b/integralimg_test.go
@@ -0,0 +1,60 @@
+// Copyright 2020 Nick White.
+// Use of this source code is governed by the GPLv3
+// license that can be found in the LICENSE file.
+
+package integralimg
+
+import (
+	"image"
+	"image/draw"
+	_ "image/png"
+	"os"
+	"testing"
+)
+
+func TestFromPNG(t *testing.T) {
+	f, err := os.Open("testdata/in.png")
+	if err != nil {
+		t.Fatalf("Could not open file %s: %v\n", "testdata/in.png", err)
+	}
+	defer f.Close()
+	img, _, err := image.Decode(f)
+	if err != nil {
+		t.Fatalf("Could not decode image: %v\n", err)
+	}
+	b := img.Bounds()
+	gray := image.NewGray(image.Rect(0, 0, b.Dx(), b.Dy()))
+	draw.Draw(gray, b, img, b.Min, draw.Src)
+
+	integral := ToIntegralImg(gray)
+
+	if !imgsequal(img, integral) {
+		t.Errorf("Read png image differs to integral\n")
+	}
+}
+
+func imgsequal(img1, img2 image.Image) bool {
+	b := img1.Bounds()
+	if !b.Eq(img2.Bounds()) {
+		return false
+	}
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			r0, g0, b0, a0 := img1.At(x, y).RGBA()
+			r1, g1, b1, a1 := img2.At(x, y).RGBA()
+			if r0 != r1 {
+				return false
+			}
+			if g0 != g1 {
+				return false
+			}
+			if b0 != b1 {
+				return false
+			}
+			if a0 != a1 {
+				return false
+			}
+		}
+	}
+	return true
+}
diff --git a/testdata/in.png b/testdata/in.png
new file mode 100644
index 0000000..8f90f19
Binary files /dev/null and b/testdata/in.png differ
-- 
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