1 files changed, 33 insertions, 3 deletions

diff --git a/src/pkg/bytes/bytes_test.go b/src/pkg/bytes/bytes_test.go
index ab5da4fbf..394dd7a44 100644
--- a/src/pkg/bytes/bytes_test.go
+++ b/src/pkg/bytes/bytes_test.go
@@ -785,6 +785,16 @@ func TestMap(t *testing.T) {
 	if string(m) != expect {
 		t.Errorf("drop: expected %q got %q", expect, m)
 	}
+
+	// 6. Invalid rune
+	invalidRune := func(r rune) rune {
+		return utf8.MaxRune + 1
+	}
+	m = Map(invalidRune, []byte("x"))
+	expect = "\uFFFD"
+	if string(m) != expect {
+		t.Errorf("invalidRune: expected %q got %q", expect, m)
+	}
 }
 
 func TestToUpper(t *testing.T) { runStringTests(t, ToUpper, "ToUpper", upperTests) }
@@ -1073,6 +1083,8 @@ var TitleTests = []TitleTest{
 	{"123a456", "123a456"},
 	{"double-blind", "Double-Blind"},
 	{"ÿøû", "Ÿøû"},
+	{"with_underscore", "With_underscore"},
+	{"unicode \xe2\x80\xa8 line separator", "Unicode \xe2\x80\xa8 Line Separator"},
 }
 
 func TestTitle(t *testing.T) {
@@ -1132,7 +1144,7 @@ func TestEqualFold(t *testing.T) {
 func TestBufferGrowNegative(t *testing.T) {
 	defer func() {
 		if err := recover(); err == nil {
-			t.Fatal("Grow(-1) should have paniced")
+			t.Fatal("Grow(-1) should have panicked")
 		}
 	}()
 	var b Buffer
@@ -1142,7 +1154,7 @@ func TestBufferGrowNegative(t *testing.T) {
 func TestBufferTruncateNegative(t *testing.T) {
 	defer func() {
 		if err := recover(); err == nil {
-			t.Fatal("Truncate(-1) should have paniced")
+			t.Fatal("Truncate(-1) should have panicked")
 		}
 	}()
 	var b Buffer
@@ -1152,7 +1164,7 @@ func TestBufferTruncateNegative(t *testing.T) {
 func TestBufferTruncateOutOfRange(t *testing.T) {
 	defer func() {
 		if err := recover(); err == nil {
-			t.Fatal("Truncate(20) should have paniced")
+			t.Fatal("Truncate(20) should have panicked")
 		}
 	}()
 	var b Buffer
@@ -1160,6 +1172,24 @@ func TestBufferTruncateOutOfRange(t *testing.T) {
 	b.Truncate(20)
 }
 
+var containsTests = []struct {
+	b, subslice []byte
+	want        bool
+}{
+	{[]byte("hello"), []byte("hel"), true},
+	{[]byte("日本語"), []byte("日本"), true},
+	{[]byte("hello"), []byte("Hello, world"), false},
+	{[]byte("東京"), []byte("京東"), false},
+}
+
+func TestContains(t *testing.T) {
+	for _, tt := range containsTests {
+		if got := Contains(tt.b, tt.subslice); got != tt.want {
+			t.Errorf("Contains(%q, %q) = %v, want %v", tt.b, tt.subslice, got, tt.want)
+		}
+	}
+}
+
 var makeFieldsInput = func() []byte {
 	x := make([]byte, 1<<20)
 	// Input is ~10% space, ~10% 2-byte UTF-8, rest ASCII non-space.