source: downloads/boost_1_33_1/tools/build/v2/test/testing-primitives/bootstrap.jam @ 12

# Proof-of-concept for bjam-based testing mechanism. This file should
# work on NT, Cygwin, and Linux. No promises for other platforms.

# Set a variable which says how to dump a file to stdout
if $(NT)
{ 
    CATENATE = type ;
}
else
{
    CATENATE = cat ;
}

# invoke the given action rule `act' to build target from sources
rule do-make ( target : sources * : act )
{
    DEPENDS $(target) : $(sources) ;
    $(act) $(target) : $(sources) ;
}

# top-level version of do-make which causes target to be built by
# default
rule make ( target : sources * : act )
{
    DEPENDS all : $(target) ;
    do-make $(target) : $(sources) : $(act) ;
}

# cause `target' to exist and building to succeed if invoking
#
#    $(act) $(target) : $(sources)
#
# fails, and to fail if the action succeeds.
rule make-fail ( target : sources * : act )
{
    # Establish another logical target which refers to the same file,
    # by using different grist.
    DEPENDS all : <different-grist>$(target) ;
    
    # Make the new logical target depend on the target
    DEPENDS <different-grist>$(target) : $(target) ;
    
    # Cause the target to be built from sources using $(act).
    do-make $(target) : $(sources) : $(act) ;
    
    # Note that we expect target to fail to build
    FAIL_EXPECTED $(target) ;
    
    # Build a failure marker file. Because targets are only built if
    # all their dependents "succeed", the marker will only be
    # generated if $(target) failed to build, as expected.
    failure-marker <different-grist>$(target) ;
}

# Simple action rules which write text into the target. Different
# names for different purposes.
actions failure-marker
{
    echo failed as expected > $(<)
}

actions create
{
    echo creating > $(<)
}

# An action which will always fail, for testing expected failure rules
actions fail-to-create
{
    exit 1
}

# Basic rule-action pair which builds the target by executing the
# given commands
rule do-run ( target : commands + )
{
    COMMANDS on $(target) = $(commands) ;
    NOTFILE $(commands) ;
}

# Run commands, leaving the output behind in $(<:S=.out). Echo to
# stdout if the command fails.
#
#  Detailed explanation:
#
#  $(COMMANDS)                          Run commands
#       > $(<:S=.out)                   into the output file
#       2>&1                            including stderr
#     &&                                and if that succeeds
#       cp -f $(<:S=.out) $(<)          copy the output file into the target
#  ||                                   otherwise
#     ( $(CATENATE) $(<:S=.out)         dump any output to stdout
#       && exit 1                       and exit with an error code
#     )
actions do-run
{
    $(COMMANDS) > $(<:S=.out) 2>&1 && cp -f $(<:S=.out) $(<) || ( $(CATENATE) $(<:S=.out) && exit 1 )
}

# top-level version of do-run which causes target to be built by
# default
rule run ( target : commands + )
{
    DEPENDS all : $(target) ;
    do-run $(target) : $(commands) ;
}

# experimental expected-failure version of run. This doesn't have
# quite the right semantics w.r.t. output dumping (it is still only
# dumped if the run fails), but we don't need run-fail anyway so it
# doesn't matter too much.
rule run-fail ( target : commands + )
{
    make-fail $(target) : $(commands) : do-run ;
}

# A command which will always fail to run.  There is no file called
# nonexistent, so executing $(error) always causes an error. We can't
# just use `exit 1' below because that will cause all command
# processing to stop, and we want the rest of the do-run action
# command-line to execute.
error = $(CATENATE)" nonexistent" ;

make-fail t1.txt : : create ;
make-fail t2.txt : : fail-to-create ;
make t3.txt : : create ;
make t4.txt : : fail-to-create ;

run t5.txt : "( echo failing t5 && $(error) )" ;
run t6.txt : echo hi ;

run-fail t7.txt : "( echo failing t7 && $(error) )" ;
run-fail t8.txt : echo hi ;