test/spec has it's own "assert_include" which is part of ZenTest. In
the default Test::Unit, you check if an array "a" contains an element
"@truffles" with:
assert_send [a, :include?, @truffles]
This is a bit nicer in zentest:
assert_includes @truffles, a
And is very pretty indeed with test/spec:
a.should.include @truffles
