pg_dump -> \i infile

I am doing some unit testing of my application code, which requires me
to often reset my Postgres 7.3.2 (Cygwin) development database to
certain known data. The problem that I am running into seems to be
this: if I try to load a database (schema and data) using the
"\i filename" command in psql, it fails. However, it works fine when I
try to load the exact same file from outside of the psql client (i.e.,
my bash shell in Cygwin) using the "psql -d databasename -f filename"
command.

Is there a way to get a file dumped from postgres using pg_dump to be
read using the "\i" command? If not, is there a way to export the
database (schema and data) to a format that can be read from the "\i"
command?

Regards,

Erik