1 files changed, 116 insertions, 0 deletions
diff --git a/src/encoding/json/fold_test.go b/src/encoding/json/fold_test.go
new file mode 100644
index 000000000..9fb94646a
--- /dev/null
+++ b/src/encoding/json/fold_test.go
@@ -0,0 +1,116 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+	"unicode/utf8"
+)
+
+var foldTests = []struct {
+	fn   func(s, t []byte) bool
+	s, t string
+	want bool
+}{
+	{equalFoldRight, "", "", true},
+	{equalFoldRight, "a", "a", true},
+	{equalFoldRight, "", "a", false},
+	{equalFoldRight, "a", "", false},
+	{equalFoldRight, "a", "A", true},
+	{equalFoldRight, "AB", "ab", true},
+	{equalFoldRight, "AB", "ac", false},
+	{equalFoldRight, "sbkKc", "ſbKKc", true},
+	{equalFoldRight, "SbKkc", "ſbKKc", true},
+	{equalFoldRight, "SbKkc", "ſbKK", false},
+	{equalFoldRight, "e", "é", false},
+	{equalFoldRight, "s", "S", true},
+
+	{simpleLetterEqualFold, "", "", true},
+	{simpleLetterEqualFold, "abc", "abc", true},
+	{simpleLetterEqualFold, "abc", "ABC", true},
+	{simpleLetterEqualFold, "abc", "ABCD", false},
+	{simpleLetterEqualFold, "abc", "xxx", false},
+
+	{asciiEqualFold, "a_B", "A_b", true},
+	{asciiEqualFold, "aa@", "aa`", false}, // verify 0x40 and 0x60 aren't case-equivalent
+}
+
+func TestFold(t *testing.T) {
+	for i, tt := range foldTests {
+		if got := tt.fn([]byte(tt.s), []byte(tt.t)); got != tt.want {
+			t.Errorf("%d. %q, %q = %v; want %v", i, tt.s, tt.t, got, tt.want)
+		}
+		truth := strings.EqualFold(tt.s, tt.t)
+		if truth != tt.want {
+			t.Errorf("strings.EqualFold doesn't agree with case %d", i)
+		}
+	}
+}
+
+func TestFoldAgainstUnicode(t *testing.T) {
+	const bufSize = 5
+	buf1 := make([]byte, 0, bufSize)
+	buf2 := make([]byte, 0, bufSize)
+	var runes []rune
+	for i := 0x20; i <= 0x7f; i++ {
+		runes = append(runes, rune(i))
+	}
+	runes = append(runes, kelvin, smallLongEss)
+
+	funcs := []struct {
+		name   string
+		fold   func(s, t []byte) bool
+		letter bool // must be ASCII letter
+		simple bool // must be simple ASCII letter (not 'S' or 'K')
+	}{
+		{
+			name: "equalFoldRight",
+			fold: equalFoldRight,
+		},
+		{
+			name:   "asciiEqualFold",
+			fold:   asciiEqualFold,
+			simple: true,
+		},
+		{
+			name:   "simpleLetterEqualFold",
+			fold:   simpleLetterEqualFold,
+			simple: true,
+			letter: true,
+		},
+	}
+
+	for _, ff := range funcs {
+		for _, r := range runes {
+			if r >= utf8.RuneSelf {
+				continue
+			}
+			if ff.letter && !isASCIILetter(byte(r)) {
+				continue
+			}
+			if ff.simple && (r == 's' || r == 'S' || r == 'k' || r == 'K') {
+				continue
+			}
+			for _, r2 := range runes {
+				buf1 := append(buf1[:0], 'x')
+				buf2 := append(buf2[:0], 'x')
+				buf1 = buf1[:1+utf8.EncodeRune(buf1[1:bufSize], r)]
+				buf2 = buf2[:1+utf8.EncodeRune(buf2[1:bufSize], r2)]
+				buf1 = append(buf1, 'x')
+				buf2 = append(buf2, 'x')
+				want := bytes.EqualFold(buf1, buf2)
+				if got := ff.fold(buf1, buf2); got != want {
+					t.Errorf("%s(%q, %q) = %v; want %v", ff.name, buf1, buf2, got, want)
+				}
+			}
+		}
+	}
+}
+
+func isASCIILetter(b byte) bool {
+	return ('A' <= b && b <= 'Z') || ('a' <= b && b <= 'z')
+}