fixes error in forward middle snake search

Author: mb0

diff.go

@@ -113,7 +113,7 @@ func (c *context) findMiddleSnake(aoffset, boffset, alimit, blimit int) (int, in
 	for d := 0; d <= maxd; d++ {
 		// forward search
 		for k := fmid - d; k <= fmid+d; k += 2 {
-			if k == fmid-d || k != fmid+d && c.forward[foff+k+1] < c.forward[foff+k-1] {
+			if k == fmid-d || k != fmid+d && c.forward[foff+k+1] > c.forward[foff+k-1] {
 				x = c.forward[foff+k+1] // down
 			} else {
 				x = c.forward[foff+k-1] + 1 // right

diff_test.go

@@ -117,6 +117,30 @@ func TestDiffBA(t *testing.T) {
 	}
 }
 
+func TestDiffRunes(t *testing.T) {
+	d := &runes{
+		[]rune("brown fox jumps over the lazy dog"),
+		[]rune("brwn faax junps ovver the lay dago"),
+	}
+	n, m := len(d.a), len(d.b)
+	res := Diff(n, m, d)
+	echange := []Change{
+		{2, 2, 1, 0},
+		{7, 6, 1, 2},
+		{12, 12, 1, 1},
+		{18, 18, 0, 1},
+		{27, 28, 1, 0},
+		{31, 31, 0, 2},
+		{32, 34, 1, 0},
+	}
+	for i, c := range res {
+		t.Log(c)
+		if c != echange[i] {
+			t.Error("expected", echange[i], "got", c)
+		}
+	}
+}
+
 func BenchmarkDiff(b *testing.B) {
 	t := tests[len(tests)-1]
 	d := &ints{t.a, t.b}

example_test.go

@@ -9,9 +9,9 @@ import (
 	"github.com/mb0/diff"
 )
 
-var names = map[string]int {
-	"one": 1,
-	"two": 2,
+var names = map[string]int{
+	"one":   1,
+	"two":   2,
 	"three": 3,
 }