first, your value on the is tests are missing a "\n":

is( $got3, "#$var#", "''''");
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Anyway, it seems that "verbatim fields" and "width specifications" (with or w/o "+") don't mix. so, the only test I could make work was:

# exactly seven chars in the field:
my $got3 = form "#{'''''}#", $var; 
is( $got3, "#$var#\n", "'''''");
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Update: apparently this also works:

my $got1 = form "#{'(7)'}#", $var;
is( $got1, "#$var#\n", "'(7)'");
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