🔒 SASL: Add "#done?" [🚧 WIP]

The protocol client is responsible for raising an error if the command
completes successfully but "done?" returns false.

lib/net/imap/sasl/cram_md5_authenticator.rb

@@ -17,8 +17,12 @@ class Net::IMAP::SASL::CramMD5Authenticator
   def process(challenge)
     digest = hmac_md5(challenge, @password)
     return @user + " " + digest
+  ensure
+    @done = true
   end
 
+  def done?; @done end
+
   private
 
   def initialize(user, password, warn_deprecation: true, **_ignored)
@@ -28,6 +32,7 @@ def initialize(user, password, warn_deprecation: true, **_ignored)
     require "digest/md5"
     @user = user
     @password = password
+    @done = false
   end
 
   def hmac_md5(text, key)

lib/net/imap/sasl/login_authenticator.rb

@@ -24,14 +24,17 @@ def process(data)
       @state = STATE_PASSWORD
       return @user
     when STATE_PASSWORD
+      @state = STATE_DONE
       return @password
+    when STATE_DONE
+      raise ResponseParseError, data
     end
   end
 
-  private
-
-  STATE_USER = :USER
+  STATE_USER     = :USER
   STATE_PASSWORD = :PASSWORD
+  STATE_DONE     = :DONE
+  private_constant :STATE_USER, :STATE_PASSWORD, :STATE_DONE
 
   def initialize(user, password, warn_deprecation: true, **_ignored)
     if warn_deprecation
@@ -42,4 +45,5 @@ def initialize(user, password, warn_deprecation: true, **_ignored)
     @state = STATE_USER
   end
 
+  def done?; @state == STATE_DONE end
 end