variable i
    variable n
    variable v
    variable msg
    variable expected

testConstraint testchannel      [llength [info commands testchannel]]
testConstraint exec             [llength [info commands exec]]
testConstraint openpipe         1
testConstraint fileevent        [llength [info commands fileevent]]
testConstraint fcopy            [llength [info commands fcopy]]
testConstraint testfevent       [llength [info commands testfevent]]
testConstraint testchannelevent [llength [info commands testchannelevent]]
testConstraint testmainthread   [llength [info commands testmainthread]]
testConstraint thread [expr {0 == [catch {package require Thread 2.7-}]}]
testConstraint testobj		[llength [info commands testobj]]

# You need a *very* special environment to do some tests.  In
# particular, many file systems do not support large-files...
testConstraint largefileSupport [expr {$::tcl_platform(os) ne "Darwin"}]

# some tests can only be run is umask is 2