From 859112b5e1516236b36e4faaa95ab5e4029c2f6c Mon Sep 17 00:00:00 2001
From: Nick White <git@njw.name>
Date: Thu, 28 Mar 2019 10:45:52 +0000
Subject: Improve tests; test regular sauvola, and add option to update golden
 files

---
 binarize/sauvola_test.go                   |  38 +++++++++++++++++++++++------
 binarize/testdata/pg1_sauvola_k0.3_w19.png | Bin 0 -> 19447 bytes
 binarize/testdata/pg1_sauvola_k0.5_w19.png | Bin 0 -> 18231 bytes
 binarize/testdata/pg1_sauvola_k0.5_w41.png | Bin 0 -> 18275 bytes
 4 files changed, 31 insertions(+), 7 deletions(-)
 create mode 100644 binarize/testdata/pg1_sauvola_k0.3_w19.png
 create mode 100644 binarize/testdata/pg1_sauvola_k0.5_w19.png
 create mode 100644 binarize/testdata/pg1_sauvola_k0.5_w41.png

diff --git a/binarize/sauvola_test.go b/binarize/sauvola_test.go
index 12a040a..6e767ab 100644
--- a/binarize/sauvola_test.go
+++ b/binarize/sauvola_test.go
@@ -1,6 +1,7 @@
 package binarize
 
 import (
+	"flag"
 	"fmt"
 	"image"
 	"image/draw"
@@ -9,6 +10,8 @@ import (
 	"testing"
 )
 
+var update = flag.Bool("update", false, "update golden files")
+
 func decode(s string) (*image.Gray, error) {
 	f, err := os.Open(s)
 	defer f.Close()
@@ -52,32 +55,53 @@ func imgsequal(img1 *image.Gray, img2 *image.Gray) bool {
 }
 
 func TestBinarization(t *testing.T) {
-	// TODO: test non-integral sauvola method too
 	cases := []struct {
 		name string
 		orig string
-		done string
+		golden string
 		ksize float64
 		wsize int
 	}{
 		{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.5_w41.png", 0.5, 41},
 		{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.5_w19.png", 0.5, 19},
 		{"integralsauvola", "testdata/pg1.png", "testdata/pg1_integralsauvola_k0.3_w19.png", 0.3, 19},
+		{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.5_w41.png", 0.5, 41},
+		{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.5_w19.png", 0.5, 19},
+		{"sauvola", "testdata/pg1.png", "testdata/pg1_sauvola_k0.3_w19.png", 0.3, 19},
 	}
 
 	for _, c := range cases {
 		t.Run(fmt.Sprintf("%s_%0.1f_%d", c.name, c.ksize, c.wsize), func(t *testing.T) {
+			var actual *image.Gray
 			orig, err := decode(c.orig)
 			if err != nil {
 				t.Errorf("Could not open file %s: %v\n", c.orig, err)
 			}
-			done, err := decode(c.done)
+			switch c.name {
+			case "integralsauvola":
+				actual = IntegralSauvola(orig, c.ksize, c.wsize)
+			case "sauvola":
+				actual = Sauvola(orig, c.ksize, c.wsize)
+			default:
+				t.Fatalf("No method %s\n", c.name)
+			}
+			if *update {
+				f, err := os.Create(c.golden)
+				defer f.Close()
+				if err != nil {
+					t.Errorf("Could not open file %s to update: %v\n", c.golden, err)
+				}
+				err = png.Encode(f, actual)
+				if err != nil {
+					t.Errorf("Could not encode update of %s: %v\n", c.golden, err)
+				}
+			}
+			golden, err := decode(c.golden)
 			if err != nil {
-				t.Errorf("Could not open file %s: %v\n", c.done, err)
+				t.Errorf("Could not open file %s: %v\n", c.golden, err)
 			}
-			new := IntegralSauvola(orig, c.ksize, c.wsize)
-			if ! imgsequal(done, new) {
-				t.Errorf("Binarized %s differs to %s\n", c.orig, c.done)
+			if ! imgsequal(golden, actual) {
+				t.Errorf("Binarized %s differs to %s\n", c.orig, c.golden)
 			}
 		})
 	}
diff --git a/binarize/testdata/pg1_sauvola_k0.3_w19.png b/binarize/testdata/pg1_sauvola_k0.3_w19.png
new file mode 100644
index 0000000..bcd595f
Binary files /dev/null and b/binarize/testdata/pg1_sauvola_k0.3_w19.png differ
diff --git a/binarize/testdata/pg1_sauvola_k0.5_w19.png b/binarize/testdata/pg1_sauvola_k0.5_w19.png
new file mode 100644
index 0000000..8de596c
Binary files /dev/null and b/binarize/testdata/pg1_sauvola_k0.5_w19.png differ
diff --git a/binarize/testdata/pg1_sauvola_k0.5_w41.png b/binarize/testdata/pg1_sauvola_k0.5_w41.png
new file mode 100644
index 0000000..b8f50e0
Binary files /dev/null and b/binarize/testdata/pg1_sauvola_k0.5_w41.png differ
-- 
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