= itslib: test library     include "itslib.m";    itslib := load Itslib Itslib->PATH;     S_INFO: con 0;    S_WARN: con 1;    S_ERROR: con 2;    S_FATAL: con 3;    S_STIME: con 4;    S_ETIME: con 5;    ENV_VERBOSITY: con "ITS_VERBOSITY";    ENV_MFD: con "ITS_MFD";     Tconfig: adt {         verbosity: int;         mfd: ref Sys->FD;         report: fn(t: self ref Tconfig, sev: int, verb: int, msg: string);         done: fn(t: self ref Tconfig);    };     init: fn(): ref Tconfig; Itslib  provides  a simple error reporting facility for testswhich can be run by itest(1). The module must first be initialised by  calling  init  whichreturns an adt containing the verbosity setting specified forthis test run, and the message file descriptor used  to  passmessages  back  to itest.  These two items of information arepassed to the test via  the  environment  variables  ITS_VER‐BOSITY and ITS_MFD. Tconf.report(severity,verbosity,message)       Report  a  message  with  specified  severity and ver‐       bosity.  Severity  must  be  one  of  S_INFO,  S_WARN,       S_ERROR  or  S_FATAL for Information, warnings, errors       and fatal errors respectively.  Verbosity is an  inte‐       ger between 0 and 9.  For informatory messages (sever‐       ity S_INFO), the message will only be displayed if the       current  verbosity  level  is greater than or equal to       verbosity. Tconf.done()       Tell the test system that  all  significant  work  has       been  completed.  This useful when for example results       are displayed in an interactive manner  following  the       test  proper.  For recording purposes the test will be       regarded as having  finished  when  this  function  is       called, rather than when the test finally exits. == exampleA very simple test program. implement T;include "sys.m";     sys: Sys;include "draw.m";     draw: Draw;include "itslib.m";     itslib: Itslib;     Tconfig, S_INFO, S_WARN, S_ERROR, S_FATAL: import itslib; T: module{     init:     fn(ctxt: ref Draw->Context, argv: list of string);}; tconf: ref Tconfig; init(ctxt: ref Draw->Context, argv: list of string){     sys = load Sys Sys->PATH;     itslib = load Itslib Itslib->PATH;     if (itslib != nil) tconf = itslib->init();     report(S_INFO, 5, "Testing addition of 1 + 2");     x := 1 + 2;     if (x == 3)          report(S_INFO, 6, "Addition of 1 + 2 OK");     else          report(S_ERROR, 5, sys->sprint("Addition of 1 + 2 gave %d", x));} report(sev: int, verb: int, msg: string){     if (tconf != nil) tconf.report(sev, verb, msg);     else sys->print("%d:%s\n", sev, msg);} == see ALSOitest(1), sh-test(2)