✨ Allow decode_datetime to work without dquotes

This modifies the code added in #66 to make it more useful when
`date-time` is parsed as a `quoted` string (as it currently is).  I'd
prefer that ResponseParser simply parse `date-time` values as DateTime
objects, but that has backwards compatibility issues.

Author: nevans

lib/net/imap/data_encoding.rb

@@ -102,8 +102,16 @@ def self.encode_datetime(time)
     #
     # Decodes +string+ as an IMAP4 formatted "date-time".
     #
-    # Note that double quotes are not optional.  See STRFTIME.
+    # NOTE: Although double-quotes are not optional in the IMAP grammar,
+    # Net::IMAP currently parses "date-time" values as "quoted" strings and this
+    # removes the quotation marks.  To be useful for strings which have already
+    # been parsed as a quoted string, this method makes double-quotes optional.
+    #
+    # See STRFTIME.
     def self.decode_datetime(string)
+      unless string.start_with?(?") && string.end_with?(?")
+        string = '"%s"' % [string]
+      end
       DateTime.strptime(string, STRFTIME)
     end
 

test/net/imap/test_imap_data_encoding.rb

@@ -59,6 +59,8 @@ def test_decode_datetime
     expected = DateTime.new(2022, 10, 6, 1, 2, 3, "-04:00")
     actual   = Net::IMAP.decode_datetime('"06-Oct-2022 01:02:03 -0400"')
     assert_equal expected, actual
+    actual   = Net::IMAP.decode_datetime("06-Oct-2022 01:02:03 -0400")
+    assert_equal expected, actual
     actual   = Net::IMAP.parse_datetime '" 6-Oct-2022 01:02:03 -0400"'
     assert_equal expected, actual
   end
@@ -69,6 +71,8 @@ def test_decode_time
     assert_equal expected, actual
     actual   = Net::IMAP.decode_time '" 7-Nov-2020 01:02:03 -0400"'
     assert_equal expected, actual
+    actual   = Net::IMAP.parse_time "07-Nov-2020 01:02:03 -0400"
+    assert_equal expected, actual
   end
 
 end