html: move the sanity checking of the entity map from runtime

(during init) to test-time (via gotest).

R=gri
CC=golang-dev
https://golang.org/cl/3466044

src/pkg/html/entity.go

@@ -4,10 +4,6 @@
 
 package html
 
-import (
-	"utf8"
-)
-
 // entity is a map from HTML entity names to their values. The semicolon matters:
 // http://www.whatwg.org/specs/web-apps/current-work/multipage/named-character-references.html
 // lists both "amp" and "amp;" as two separate entries.
@@ -2252,19 +2248,3 @@ var entity2 = map[string][2]int{
 	"vsupnE;":                  {'\u2ACC', '\uFE00'},
 	"vsupne;":                  {'\u228B', '\uFE00'},
 }
-
-func init() {
-	// We verify that the length of UTF-8 encoding of each value is <= 1 + len(key).
-	// The +1 comes from the leading "&". This property implies that the length of
-	// unescaped text is <= the length of escaped text.
-	for k, v := range entity {
-		if 1+len(k) < utf8.RuneLen(v) {
-			panic("escaped entity &" + k + " is shorter than its UTF-8 encoding " + string(v))
-		}
-	}
-	for k, v := range entity2 {
-		if 1+len(k) < utf8.RuneLen(v[0])+utf8.RuneLen(v[1]) {
-			panic("escaped entity &" + k + " is shorter than its UTF-8 encoding " + string(v[0]) + string(v[1]))
-		}
-	}
-}

src/pkg/html/entity_test.go

+// Copyright 2010 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"
+	"utf8"
+)
+
+func TestEntityLength(t *testing.T) {
+	// We verify that the length of UTF-8 encoding of each value is <= 1 + len(key).
+	// The +1 comes from the leading "&". This property implies that the length of
+	// unescaped text is <= the length of escaped text.
+	for k, v := range entity {
+		if 1+len(k) < utf8.RuneLen(v) {
+			t.Error("escaped entity &" + k + " is shorter than its UTF-8 encoding " + string(v))
+		}
+	}
+	for k, v := range entity2 {
+		if 1+len(k) < utf8.RuneLen(v[0])+utf8.RuneLen(v[1]) {
+			t.Error("escaped entity &" + k + " is shorter than its UTF-8 encoding " + string(v[0]) + string(v[1]))
+		}
+	}
+}