-- testing (transducers mappings) ----------------------------------------

        -- testing (transducers mappings) - mappings -------------------------
        sample mapping can be expressed as equivalent alist. ......... [ PASS]
        sample mapping transduces to equivalent alist. ............... [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce mapping-fold values (collect-list) m)
        sample mapping transduces to equivalent reverse-alist. ....... [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce reverse-mapping-fold values (collect-list) m)
        flattening mappings into list produces expected alist. ....... [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce list-fold flatten-mapping (collect-list) (list m m))
        collecting enumerated list into mapping. ..................... [ PASS]
        chaining mappings produces expected alist. ................... [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce
              mapping-fold
              (chain-mapping (mapping (make-default-comparator) 2 'c 3 'd))
              (collect-list)
              (mapping (make-default-comparator) 0 'a 1 'b))
        chaining mappings in reverse produces expected alist. ........ [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce
              mapping-fold
              (chain-reverse-mapping (mapping (make-default-comparator) 2 'c 3 'd))
              (collect-list)
              (mapping (make-default-comparator) 0 'a 1 'b))
        interleaving mapping produces expected alist. ................ [ERROR]

Error: (null-list?) bad argument type - not a list: #<srfi-146#<mapping>>
            (transduce
              mapping-fold
              (interleave-mapping (mapping (make-default-comparator) 2 'c 3 'd))
              (collect-list)
              (mapping (make-default-comparator) 0 'a 1 'b))
        zipping mapping produces expected alist. ..................... [ PASS]
        9 tests completed in 0.001 seconds.
        6 errors (667/10%).
        3 out of 9 (333/10%) tests passed.
        -- done testing (transducers mappings) - mappings --------------------


        -- testing (transducers mappings) - hashmaps -------------------------
        sample hashmap can be expressed as equivalent sorted list. ... [ PASS]
        hashmap can be expressed as equivalent sorted list. .......... [ PASS]
        flattening hashmap into list produces expected alist. ........ [ PASS]
        chaining hashmap onto list produces expected alist. .......... [ PASS]
        4 tests completed in 0.0 seconds.
        4 out of 4 (100%) tests passed.
        -- done testing (transducers mappings) - hashmaps --------------------

    2 subgroups completed in 0.001 seconds.
    1 out of 2 (50%) subgroup passed.
    -- done testing (transducers mappings) -----------------------------------