Add an E2E test case with an already encrypted message

test/e2e.ini

@@ -30,7 +30,7 @@ certs: test/certs
 
 [tests]
 # Number of "test-*" sections in this file, describing test cases.
-cases: 3
+cases: 4
 python_path: /usr/local/bin/python3.8
 e2e_log: test/logs/e2e.log
 e2e_log_format: %(asctime)s %(pathname)s:%(lineno)d %(levelname)s [%(funcName)s] %(message)s
@@ -54,3 +54,9 @@ descr: Clear text message to a user with an Ed25519 key
 to: bob@disposlab
 in: test/msgin/clear2ed.msg
 out: -----BEGIN PGP MESSAGE-----
+
+[case-4]
+descr: Encrypted message to a user with an Ed25519 key
+to: bob@disposlab
+in: test/msgin/ed2ed.msg
+out: -----BEGIN PGP MESSAGE-----

test/msgin/ed2ed.msg

@@ -0,0 +1,13 @@
+From: Dave <dave@localhost>
+To: Bob <bob@localhost>
+Subject: Test
+Content-Transfer-Encoding: 7bit
+
+-----BEGIN PGP MESSAGE-----
+
+hF4DujWCoRS24dYSAQdAyGDF9Us11JDr8+XPmvlJHsMS7A4UBIcCiresJyZpSxYw
+Cqcugy5AX5fgSAiL1Cd2b1zpQ/rYdTWkFYMVbH4jBEoPC3z/aSd+hTnneJFDUdXl
+0koBDIw7NQylu6SrW+Y/DmXgalIHtwACuKivJTq/z9jdwFScV7adRR/VO53Inah3
+L1+Ho7Zta95AYW3UPu71Gw3rrkfjY4uGDiFAFg==
+=yTzD
+-----END PGP MESSAGE-----