Encoding package should initialize at import.

There is no reason to make callers execute Register().
Also, while here, let's add some test cases.

encoding/all.go

@@ -12,6 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Package encoding is used to provide a fairly complete set of encodings
+// for tcell applications.  Importing this package will automatically
+// register encodings.  Note that this package will add several MB to the
+// generated binaries, as the encodings themselves can be somewhat large,
+// particularly for the East Asian locales.
 package encoding
 
 import (
@@ -29,7 +34,13 @@ import (
 // add full character set support to your program.  Note that this can
 // add several megabytes to your program's size, because some of the encodings
 // are rather large (particularly those from East Asia.)
+//
+// Deprecated: This is no longer needed, importing the package is sufficient.
 func Register() {
+	registerAll()
+}
+
+func registerAll() {
 	// We supply latin1 and latin5, because Go doesn't
 	tcell.RegisterEncoding("ISO8859-1", encoding.ISO8859_1)
 	tcell.RegisterEncoding("ISO8859-9", encoding.ISO8859_9)
@@ -62,7 +73,7 @@ func Register() {
 
 	tcell.RegisterEncoding("Big5", traditionalchinese.Big5)
 
-	// Common aliaess
+	// Common aliases
 	aliases := map[string]string{
 		"8859-1":      "ISO8859-1",
 		"ISO-8859-1":  "ISO8859-1",
@@ -113,3 +124,7 @@ func Register() {
 		}
 	}
 }
+
+func init() {
+	registerAll();
+}

encoding/encoding_init_test.go

@@ -0,0 +1,68 @@
+// Copyright 2022 The TCell Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use file except in compliance with the License.
+// You may obtain a copy of the license at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package encoding
+
+import (
+	"testing"
+
+	"github.com/gdamore/tcell/v2"
+)
+
+func TestGBK(t *testing.T) {
+	enc := tcell.GetEncoding("GBK")
+	if enc == nil {
+		t.Fatal("NULL encoding for GBK")
+	}
+	glyph, _ := enc.NewDecoder().Bytes([]byte{0x82, 0x74})
+	if string(glyph) != "倀" {
+		t.Errorf("failed to match: %s != 倀", string(glyph))
+	}
+}
+
+func TestAscii(t *testing.T) {
+	encodings := []string{
+		"ASCII",
+		"ISO-8859-1",
+		"KOI8-R",
+		"KOI8-U",
+		"SJIS",
+		"Big5",
+		"GB2312",
+		"GB18030",
+		"EUC-JP",
+		"EUCKR",
+	}
+
+	for _, name := range encodings {
+		t.Run(name, func(t *testing.T) {
+			enc := tcell.GetEncoding(name)
+			if enc == nil {
+				t.Errorf("Failed getting encoding for %s", name)
+				return
+			}
+			encoder := enc.NewEncoder()
+			decoder := enc.NewDecoder()
+			// Ensure that all US-ASCII (lower 7 bit values) encode and decode identically
+			for i := byte(0); i < 126; i++ { // well, KOI8-R has some problem with "~"
+				s := string([]byte{i})
+				if x, err := encoder.String(s); err != nil || x != s {
+					t.Errorf("failed encoding for character: %d, err %v expect %s got %s", i, err, s, x)
+				}
+				if x, err := decoder.String(s); err != nil || x != s {
+					t.Errorf("failed decoding for character: %d, err %v expect %s got %s", i, err, s, x)
+				}
+			}
+		})
+	}
+}