Given this:

IN: scratchpad { { "a" "b" } { "a" "c" } { "a" "d" } { "b" "c" } { "b" "d" } { "c" "d" } }
IN: scratchpad { "a" "b" "c" "d" } combinations set=
==> t

Why does this fail?

IN: combinations.tests

{ { "a" "b" } { "a" "c" } { "a" "d" } { "b" "c" } { "b" "d" } { "c" "d" } } 
[ { "a" "b" "c" "d" } combinations set= ] unit-test

IN: scratchpad "combinations" test

==>
Unit Test: {
    {
        { "a" "b" }
        { "a" "c" }
        { "a" "d" }
        { "b" "c" }
        { "b" "d" }
        { "c" "d" }
    }
    [ { "a" "b" "c" "d" } combinations set= ]
}
--> test failed!