new file mode 100644
--- /dev/null
+++ b/test/tsu.ijs
@@ -0,0 +1,64 @@
+NB. test script utilities -----------------------------------------------
+
+1=#$ testpath  NB. testpath must already be defined as path to tests (with final / or \) before loading tsu.ijs
+
+testfiles=: 3 : 0   NB. y. is prefix - e.g., 'g' or 'gm' or 'gs'
+ testpath&,&.> /:~ {."1 [1!:0 testpath,y,'*.ijs'
+)
+
+ddall    =: testfiles 'g'           NB. all
+ddgmbx   =: testfiles 'gmbx'        NB. map boxed arrays
+ddgsp    =: testfiles 'gsp'         NB. sparse arrays
+ddg      =: ddall -. ddgmbx,ddgsp   NB. "ordinary"
+
+etx      =: 1 : 'x :: (<:@(13!:11)@i.@0: >@{ 9!:8@i.@0:)'
+ex       =: ". etx
+fex      =: }. @ (i.&(10{a.) {. ]) @ (13!:12) @ i. @ 0: @ (0!:110)
+
+threshold=: 0.75   NB. for timing tests
+timer    =: 6!:2
+
+type     =: 3!:0
+imax     =: IF64{:: 2147483647; 9223372036854775807
+imin     =: (-imax)-1
+
+scheck=: 3 : 0  NB. check sparse array
+ s=. $ y
+ a=. 2 $. y
+ e=. 3 $. y
+ i=. 4 $. y
+ x=. 5 $. y
+
+ assert. 1 = #$s                      NB. 0
+ assert. s -: <.s                     NB. 1
+ assert. imax >: #s                   NB. 2
+ assert. *./ (0 <: s) *. s <: imax    NB. 3
+ assert. _ > */s                      NB. 4
+
+ assert. 1 = #$a                      NB. 5
+ assert. *./ a e. i.#s                NB. 6
+ assert. a -: ~.a                     NB. 7
+
+ assert. 0 = #$e                      NB. 8
+ assert. (type e) = <. 0.001*type y   NB. 9
+ assert. (type e) = type x            NB. 10
+
+ assert. 2 = #$i                      NB. 11
+ assert. i -: <.i                     NB. 12
+ assert. imax >: #i                   NB. 13
+ assert. (#i) = #x                    NB. 14
+ assert. ({:$i) = #a                  NB. 15
+ assert. *./, (0<:i) *. i<"1 a{s      NB. 16
+ assert. i -: ~. i                    NB. 17
+ assert. i -: /:~i                    NB. 18
+
+ assert. (#$x) = 1+(#s)-#a            NB. 19
+ assert. (}.$x) -: ((i.#s)-.a){s      NB. 20
+ 1
+)
+
+comb=: 4 : 0
+ c=. 1 {.~ - d=. 1+y-x
+ z=. i.1 0
+ for_j. (d-1+y)+/&i.d do. z=. (c#j) ,. z{~;(-c){.&.><i.{.c=. +/\.c end.
+)