factory_girl

Mail::UnstructuredField#wrapped_value

2.2.3. Long Header Fields

 Each header field is logically a single line of characters comprising
 the field name, the colon, and the field body.  For convenience
 however, and to deal with the 998/78 character limitations per line,
 the field body portion of a header field can be split into a multiple
 line representation; this is called "folding".  The general rule is
 that wherever this standard allows for folding white space (not
 simply WSP characters), a CRLF may be inserted before any WSP.  For
 example, the header field:

         Subject: This is a test

 can be represented as:

         Subject: This
          is a test

 Note: Though structured field bodies are defined in such a way that
 folding can take place between many of the lexical tokens (and even
 within some of the lexical tokens), folding SHOULD be limited to
 placing the CRLF at higher-level syntactic breaks.  For instance, if
 a field body is defined as comma-separated values, it is recommended
 that folding occur after the comma separating the structured items in
 preference to other places where the field could be folded, even if
 it is allowed elsewhere.

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