html: add escaping tests

R=golang-dev, dsymonds, bradfitz
CC=golang-dev
https://golang.org/cl/11095043

src/pkg/html/escape_test.go

+// 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 html
+
+import "testing"
+
+type unescapeTest struct {
+	// A short description of the test case.
+	desc string
+	// The HTML text.
+	html string
+	// The unescaped text.
+	unescaped string
+}
+
+var unescapeTests = []unescapeTest{
+	// Handle no entities.
+	{
+		"copy",
+		"A\ttext\nstring",
+		"A\ttext\nstring",
+	},
+	// Handle simple named entities.
+	{
+		"simple",
+		"& > <",
+		"& > <",
+	},
+	// Handle hitting the end of the string.
+	{
+		"stringEnd",
+		"&amp &amp",
+		"& &",
+	},
+	// Handle entities with two codepoints.
+	{
+		"multiCodepoint",
+		"text &gesl; blah",
+		"text \u22db\ufe00 blah",
+	},
+	// Handle decimal numeric entities.
+	{
+		"decimalEntity",
+		"Delta = &#916; ",
+		"Delta = Δ ",
+	},
+	// Handle hexadecimal numeric entities.
+	{
+		"hexadecimalEntity",
+		"Lambda = &#x3bb; = &#X3Bb ",
+		"Lambda = λ = λ ",
+	},
+	// Handle numeric early termination.
+	{
+		"numericEnds",
+		"&# &#x &#128;43 &copy = &#169f = &#xa9",
+		"&# &#x €43 © = ©f = ©",
+	},
+	// Handle numeric ISO-8859-1 entity replacements.
+	{
+		"numericReplacements",
+		"Footnote&#x87;",
+		"Footnote‡",
+	},
+}
+
+func TestUnescape(t *testing.T) {
+	for _, tt := range unescapeTests {
+		unescaped := UnescapeString(tt.html)
+		if unescaped != tt.unescaped {
+			t.Errorf("TestUnescape %s: want %q, got %q", tt.desc, tt.unescaped, unescaped)
+		}
+	}
+}
+
+func TestUnescapeEscape(t *testing.T) {
+	ss := []string{
+		``,
+		`abc def`,
+		`a & b`,
+		`a&amp;b`,
+		`a &amp b`,
+		`&quot;`,
+		`"`,
+		`"<&>"`,
+		`&quot;&lt;&amp;&gt;&quot;`,
+		`3&5==1 && 0<1, "0&lt;1", a+acute=&aacute;`,
+		`The special characters are: <, >, &, ' and "`,
+	}
+	for _, s := range ss {
+		if got := UnescapeString(EscapeString(s)); got != s {
+			t.Errorf("got %q want %q", got, s)
+		}
+	}
+}