Moved the test codec definition to a new module and updated the test and

codec to test all charmap codec features.

As side-effect of moving the test codec into a new module, the encodings
package codec import mechanism is checked as well.

Lib/test/testcodec.py

@@ -0,0 +1,49 @@
+""" Test Codecs (used by test_charmapcodec)
+
+Written by Marc-Andre Lemburg (mal@lemburg.com).
+
+(c) Copyright 2000 Guido van Rossum.
+
+"""#"
+import codecs
+
+### Codec APIs
+
+class Codec(codecs.Codec):
+
+    def encode(self,input,errors='strict'):
+
+        return codecs.charmap_encode(input,errors,encoding_map)
+        
+    def decode(self,input,errors='strict'):
+
+        return codecs.charmap_decode(input,errors,decoding_map)
+
+class StreamWriter(Codec,codecs.StreamWriter):
+    pass
+        
+class StreamReader(Codec,codecs.StreamReader):
+    pass
+
+### encodings module API
+
+def getregentry():
+
+    return (Codec().encode,Codec().decode,StreamReader,StreamWriter)
+
+### Decoding Map
+
+decoding_map = codecs.make_identity_dict(range(256))
+decoding_map.update({
+        0x78: u"abc", # 1-n decoding mapping
+        "abc": 0x0078,# 1-n encoding mapping
+        0x01: None,   # decoding mapping to <undefined>
+        0x79: u"",    # decoding mapping to <remove character>
+})
+
+### Encoding Map
+
+encoding_map = {}
+for k,v in decoding_map.items():
+    encoding_map[v] = k
+