goprotobuf: Fix documentation of minor edge case in CamelCase.

Fixes #42.

R=r
CC=golang-dev
https://codereview.appspot.com/12767050

protoc-gen-go/generator/generator.go

@@ -1781,7 +1781,7 @@ func isASCIIDigit(c byte) bool {
 // but it's so remote we're prepared to pretend it's nonexistent - since the
 // C++ generator lowercases names, it's extremely unlikely to have two fields
 // with different capitalizations.
-// In short, _my_field_name_2 becomes XMyFieldName2.
+// In short, _my_field_name_2 becomes XMyFieldName_2.
 func CamelCase(s string) string {
 	if s == "" {
 		return ""

protoc-gen-go/generator/name_test.go

@@ -0,0 +1,56 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2013 The Go Authors.  All rights reserved.
+// http://code.google.com/p/goprotobuf/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package generator
+
+import (
+	"testing"
+)
+
+func TestCamelCase(t *testing.T) {
+	tests := []struct {
+		in, want string
+	}{
+		{"one", "One"},
+		{"one_two", "OneTwo"},
+		{"_my_field_name_2", "XMyFieldName_2"},
+		{"Something_Capped", "Something_Capped"},
+		{"my_Name", "My_Name"},
+		{"OneTwo", "OneTwo"},
+		{"_", "X"},
+		{"_a_", "XA_"},
+	}
+	for _, tc := range tests {
+		if got := CamelCase(tc.in); got != tc.want {
+			t.Errorf("CamelCase(%q) = %q, want %q", tc.in, got, tc.want)
+		}
+	}
+}