Add a script to check for coverage nondeterminism

  o Minor features (testing):

    - We now have a script, cov-test-determinism.sh, to identify places

      where our unit test coverage has become nondeterministic.

      Closes ticket 29436.

#!/bin/sh

# To use this script, build Tor with coverage enabled, and then say:

#  ./scripts/test/cov-test-determinism.sh run

#

# Let it run for a long time so it can run the tests over and over.  It

# will put their coverage outputs in coverage-raw/coverage-*/.

#

# Then say:

#  ./scripts/test/cov-test-determinism.sh check

#

# It will diff the other coverage outputs to the first one, and put their

# diffs in coverage-raw/diff-coverage-*.

run=0

check=0

if test "$1" = run; then

    run=1

elif test "$1" = check; then

    check=1

else

    echo "First use 'run' with this script, then use 'check'."

    exit 1

fi

if test "$run" = 1; then

    while true; do

        make reset-gcov

        CD=coverage-raw/coverage-$(date +%s)

        make -j5 check

        mkdir -p "$CD"

        ./scripts/test/coverage "$CD"

    done

fi

if test "$check" = 1; then

    cd coverage-raw || exit 1

    FIRST="$(find . -name "coverage-*" -type d | head -1)"

    rm -f A

    ln -sf "$FIRST" A

    for dir in coverage-*; do

        rm -f B

        ln -sf "$dir" B

        ../scripts/test/cov-diff A B > "diff-$dir"

    done

fi