✅🐛 Fix FakeServer CommandParseError (tests only)

Author: nevans

test/net/imap/fake_server/command_reader.rb

@@ -3,7 +3,7 @@
 require "net/imap"
 
 class Net::IMAP::FakeServer
-  CommandParseError = RuntimeError
+  CommandParseError = Class.new(RuntimeError)
 
   class CommandReader
     attr_reader :last_command
@@ -46,7 +46,7 @@ def get_command
     # TODO: convert bad command exception to tagged BAD response, when possible
     def parse(buf)
       /\A([^ ]+) ((?:UID )?\w+)(?: (.+))?\r\n\z/min =~ buf or
-        raise CommandParseError, "bad request: %p" [buf]
+        raise CommandParseError, "bad request: %p" % [buf]
       case $2.upcase
       when "LOGIN", "SELECT", "EXAMINE", "ENABLE", "AUTHENTICATE"
         Command.new $1, $2, scan_astrings($3), buf