add glib testing TAP utilities

4 files changed, 794 insertions, 1 deletions

diff --git a/utils/Makefile.am b/utils/Makefile.am
index be24c17f..8af5c8f7 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -1,4 +1,6 @@
 EXTRA_DIST = \
 	file2header.sh \
 	irssi-version.sh \
-	syntax.pl
+	syntax.pl \
+	tap-driver.sh \
+	tap-test
diff --git a/utils/glib-tap.mk b/utils/glib-tap.mk
new file mode 100644
index 00000000..582f6d29
--- /dev/null
+++ b/utils/glib-tap.mk
@@ -0,0 +1,134 @@
+# GLIB - Library of useful C routines
+
+TESTS_ENVIRONMENT= \
+	G_TEST_SRCDIR="$(abs_srcdir)" 		\
+	G_TEST_BUILDDIR="$(abs_builddir)" 	\
+	G_DEBUG=gc-friendly 			\
+	MALLOC_CHECK_=2 			\
+	MALLOC_PERTURB_=$$(($${RANDOM:-256} % 256))
+LOG_DRIVER = env AM_TAP_AWK='$(AWK)' $(SHELL) $(top_srcdir)/utils/tap-driver.sh
+LOG_COMPILER = $(top_srcdir)/utils/tap-test
+
+NULL =
+
+# initialize variables for unconditional += appending
+BUILT_SOURCES =
+BUILT_EXTRA_DIST =
+CLEANFILES = *.log *.trs
+DISTCLEANFILES =
+MAINTAINERCLEANFILES =
+EXTRA_DIST =
+TESTS =
+
+installed_test_LTLIBRARIES =
+installed_test_PROGRAMS =
+installed_test_SCRIPTS =
+nobase_installed_test_DATA =
+
+noinst_LTLIBRARIES =
+noinst_PROGRAMS =
+noinst_SCRIPTS =
+noinst_DATA =
+
+check_LTLIBRARIES =
+check_PROGRAMS =
+check_SCRIPTS =
+check_DATA =
+
+# We support a fairly large range of possible variables.  It is expected that all types of files in a test suite
+# will belong in exactly one of the following variables.
+#
+# First, we support the usual automake suffixes, but in lowercase, with the customary meaning:
+#
+#   test_programs, test_scripts, test_data, test_ltlibraries
+#
+# The above are used to list files that are involved in both uninstalled and installed testing.  The
+# test_programs and test_scripts are taken to be actual testcases and will be run as part of the test suite.
+# Note that _data is always used with the nobase_ automake variable name to ensure that installed test data is
+# installed in the same way as it appears in the package layout.
+#
+# In order to mark a particular file as being only for one type of testing, use 'installed' or 'uninstalled',
+# like so:
+#
+#   installed_test_programs, uninstalled_test_programs
+#   installed_test_scripts, uninstalled_test_scripts
+#   installed_test_data, uninstalled_test_data
+#   installed_test_ltlibraries, uninstalled_test_ltlibraries
+#
+# Additionally, we support 'extra' infixes for programs and scripts.  This is used for support programs/scripts
+# that should not themselves be run as testcases (but exist to be used from other testcases):
+#
+#   test_extra_programs, installed_test_extra_programs, uninstalled_test_extra_programs
+#   test_extra_scripts, installed_test_extra_scripts, uninstalled_test_extra_scripts
+#
+# Additionally, for _scripts and _data, we support the customary dist_ prefix so that the named script or data
+# file automatically end up in the tarball.
+#
+#   dist_test_scripts, dist_test_data, dist_test_extra_scripts
+#   dist_installed_test_scripts, dist_installed_test_data, dist_installed_test_extra_scripts
+#   dist_uninstalled_test_scripts, dist_uninstalled_test_data, dist_uninstalled_test_extra_scripts
+#
+# Note that no file is automatically disted unless it appears in one of the dist_ variables.  This follows the
+# standard automake convention of not disting programs scripts or data by default.
+#
+# test_programs, test_scripts, uninstalled_test_programs and uninstalled_test_scripts (as well as their disted
+# variants) will be run as part of the in-tree 'make check'.  These are all assumed to be runnable under
+# gtester.  That's a bit strange for scripts, but it's possible.
+
+TESTS += $(test_programs) $(test_scripts) $(uninstalled_test_programs) $(uninstalled_test_scripts) \
+         $(dist_test_scripts) $(dist_uninstalled_test_scripts)
+
+# Note: build even the installed-only targets during 'make check' to ensure that they still work.
+# We need to do a bit of trickery here and manage disting via EXTRA_DIST instead of using dist_ prefixes to
+# prevent automake from mistreating gmake functions like $(wildcard ...) and $(addprefix ...) as if they were
+# filenames, including removing duplicate instances of the opening part before the space, eg. '$(addprefix'.
+all_test_programs     = $(test_programs) $(uninstalled_test_programs) $(installed_test_programs) \
+                        $(test_extra_programs) $(uninstalled_test_extra_programs) $(installed_test_extra_programs)
+all_test_scripts      = $(test_scripts) $(uninstalled_test_scripts) $(installed_test_scripts) \
+                        $(test_extra_scripts) $(uninstalled_test_extra_scripts) $(installed_test_extra_scripts)
+all_dist_test_scripts = $(dist_test_scripts) $(dist_uninstalled_test_scripts) $(dist_installed_test_scripts) \
+                        $(dist_test_extra_scripts) $(dist_uninstalled_test_extra_scripts) $(dist_installed_test_extra_scripts)
+all_test_scripts     += $(all_dist_test_scripts)
+EXTRA_DIST           += $(all_dist_test_scripts)
+all_test_data         = $(test_data) $(uninstalled_test_data) $(installed_test_data)
+all_dist_test_data    = $(dist_test_data) $(dist_uninstalled_test_data) $(dist_installed_test_data)
+all_test_data        += $(all_dist_test_data)
+EXTRA_DIST           += $(all_dist_test_data)
+all_test_ltlibs       = $(test_ltlibraries) $(uninstalled_test_ltlibraries) $(installed_test_ltlibraries)
+
+if ENABLE_ALWAYS_BUILD_TESTS
+noinst_LTLIBRARIES += $(all_test_ltlibs)
+noinst_PROGRAMS += $(all_test_programs)
+noinst_SCRIPTS += $(all_test_scripts)
+noinst_DATA += $(all_test_data)
+else
+check_LTLIBRARIES += $(all_test_ltlibs)
+check_PROGRAMS += $(all_test_programs)
+check_SCRIPTS += $(all_test_scripts)
+check_DATA += $(all_test_data)
+endif
+
+if ENABLE_INSTALLED_TESTS
+installed_test_PROGRAMS += $(test_programs) $(installed_test_programs) \
+                          $(test_extra_programs) $(installed_test_extra_programs)
+installed_test_SCRIPTS += $(test_scripts) $(installed_test_scripts) \
+                          $(test_extra_scripts) $(test_installed_extra_scripts)
+installed_test_SCRIPTS += $(dist_test_scripts) $(dist_test_extra_scripts) \
+                          $(dist_installed_test_scripts) $(dist_installed_test_extra_scripts)
+nobase_installed_test_DATA += $(test_data) $(installed_test_data)
+nobase_installed_test_DATA += $(dist_test_data) $(dist_installed_test_data)
+installed_test_LTLIBRARIES += $(test_ltlibraries) $(installed_test_ltlibraries)
+installed_testcases = $(test_programs) $(installed_test_programs) \
+                      $(test_scripts) $(installed_test_scripts) \
+                      $(dist_test_scripts) $(dist_installed_test_scripts)
+
+installed_test_meta_DATA = $(installed_testcases:=.test)
+
+%.test: %$(EXEEXT) Makefile
+	$(AM_V_GEN) (echo '[Test]' > $@.tmp; \
+	echo 'Type=session' >> $@.tmp; \
+	echo 'Exec=$(installed_testdir)/$<' >> $@.tmp; \
+	mv $@.tmp $@)
+
+CLEANFILES += $(installed_test_meta_DATA)
+endif
diff --git a/utils/tap-driver.sh b/utils/tap-driver.sh
new file mode 100755
index 00000000..19aa531d
--- /dev/null
+++ b/utils/tap-driver.sh
@@ -0,0 +1,652 @@
+#! /bin/sh
+# Copyright (C) 2011-2013 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# This file is maintained in Automake, please report
+# bugs to <bug-automake@gnu.org> or send patches to
+# <automake-patches@gnu.org>.
+
+scriptversion=2011-12-27.17; # UTC
+
+# Make unconditional expansion of undefined variables an error.  This
+# helps a lot in preventing typo-related bugs.
+set -u
+
+me=tap-driver.sh
+
+fatal ()
+{
+  echo "$me: fatal: $*" >&2
+  exit 1
+}
+
+usage_error ()
+{
+  echo "$me: $*" >&2
+  print_usage >&2
+  exit 2
+}
+
+print_usage ()
+{
+  cat <<END
+Usage:
+  tap-driver.sh --test-name=NAME --log-file=PATH --trs-file=PATH
+                [--expect-failure={yes|no}] [--color-tests={yes|no}]
+                [--enable-hard-errors={yes|no}] [--ignore-exit]
+                [--diagnostic-string=STRING] [--merge|--no-merge]
+                [--comments|--no-comments] [--] TEST-COMMAND
+The \`--test-name', \`--log-file' and \`--trs-file' options are mandatory.
+END
+}
+
+# TODO: better error handling in option parsing (in particular, ensure
+# TODO: $log_file, $trs_file and $test_name are defined).
+test_name= # Used for reporting.
+log_file=  # Where to save the result and output of the test script.
+trs_file=  # Where to save the metadata of the test run.
+expect_failure=0
+color_tests=0
+merge=0
+ignore_exit=0
+comments=0
+diag_string='#'
+while test $# -gt 0; do
+  case $1 in
+  --help) print_usage; exit $?;;
+  --version) echo "$me $scriptversion"; exit $?;;
+  --test-name) test_name=$2; shift;;
+  --log-file) log_file=$2; shift;;
+  --trs-file) trs_file=$2; shift;;
+  --color-tests) color_tests=$2; shift;;
+  --expect-failure) expect_failure=$2; shift;;
+  --enable-hard-errors) shift;; # No-op.
+  --merge) merge=1;;
+  --no-merge) merge=0;;
+  --ignore-exit) ignore_exit=1;;
+  --comments) comments=1;;
+  --no-comments) comments=0;;
+  --diagnostic-string) diag_string=$2; shift;;
+  --) shift; break;;
+  -*) usage_error "invalid option: '$1'";;
+  esac
+  shift
+done
+
+test $# -gt 0 || usage_error "missing test command"
+
+case $expect_failure in
+  yes) expect_failure=1;;
+    *) expect_failure=0;;
+esac
+
+if test $color_tests = yes; then
+  init_colors='
+    color_map["red"]="" # Red.
+    color_map["grn"]="" # Green.
+    color_map["lgn"]="" # Light green.
+    color_map["blu"]="" # Blue.
+    color_map["mgn"]="" # Magenta.
+    color_map["std"]=""     # No color.
+    color_for_result["ERROR"] = "mgn"
+    color_for_result["PASS"]  = "grn"
+    color_for_result["XPASS"] = "red"
+    color_for_result["FAIL"]  = "red"
+    color_for_result["XFAIL"] = "lgn"
+    color_for_result["SKIP"]  = "blu"'
+else
+  init_colors=''
+fi
+
+# :; is there to work around a bug in bash 3.2 (and earlier) which
+# does not always set '$?' properly on redirection failure.
+# See the Autoconf manual for more details.
+:;{
+  (
+    # Ignore common signals (in this subshell only!), to avoid potential
+    # problems with Korn shells.  Some Korn shells are known to propagate
+    # to themselves signals that have killed a child process they were
+    # waiting for; this is done at least for SIGINT (and usually only for
+    # it, in truth).  Without the `trap' below, such a behaviour could
+    # cause a premature exit in the current subshell, e.g., in case the
+    # test command it runs gets terminated by a SIGINT.  Thus, the awk
+    # script we are piping into would never seen the exit status it
+    # expects on its last input line (which is displayed below by the
+    # last `echo $?' statement), and would thus die reporting an internal
+    # error.
+    # For more information, see the Autoconf manual and the threads:
+    # <http://lists.gnu.org/archive/html/bug-autoconf/2011-09/msg00004.html>
+    # <http://mail.opensolaris.org/pipermail/ksh93-integration-discuss/2009-February/004121.html>
+    trap : 1 3 2 13 15
+    if test $merge -gt 0; then
+      exec 2>&1
+    else
+      exec 2>&3
+    fi
+    "$@"
+    echo $?
+  ) | LC_ALL=C ${AM_TAP_AWK-awk} \
+        -v me="$me" \
+        -v test_script_name="$test_name" \
+        -v log_file="$log_file" \
+        -v trs_file="$trs_file" \
+        -v expect_failure="$expect_failure" \
+        -v merge="$merge" \
+        -v ignore_exit="$ignore_exit" \
+        -v comments="$comments" \
+        -v diag_string="$diag_string" \
+'
+# FIXME: the usages of "cat >&3" below could be optimized when using
+# FIXME: GNU awk, and/on on systems that supports /dev/fd/.
+
+# Implementation note: in what follows, `result_obj` will be an
+# associative array that (partly) simulates a TAP result object
+# from the `TAP::Parser` perl module.
+
+## ----------- ##
+##  FUNCTIONS  ##
+## ----------- ##
+
+function fatal(msg)
+{
+  print me ": " msg | "cat >&2"
+  exit 1
+}
+
+function abort(where)
+{
+  fatal("internal error " where)
+}
+
+# Convert a boolean to a "yes"/"no" string.
+function yn(bool)
+{
+  return bool ? "yes" : "no";
+}
+
+function add_test_result(result)
+{
+  if (!test_results_index)
+    test_results_index = 0
+  test_results_list[test_results_index] = result
+  test_results_index += 1
+  test_results_seen[result] = 1;
+}
+
+# Whether the test script should be re-run by "make recheck".
+function must_recheck()
+{
+  for (k in test_results_seen)
+    if (k != "XFAIL" && k != "PASS" && k != "SKIP")
+      return 1
+  return 0
+}
+
+# Whether the content of the log file associated to this test should
+# be copied into the "global" test-suite.log.
+function copy_in_global_log()
+{
+  for (k in test_results_seen)
+    if (k != "PASS")
+      return 1
+  return 0
+}
+
+# FIXME: this can certainly be improved ...
+function get_global_test_result()
+{
+    if ("ERROR" in test_results_seen)
+      return "ERROR"
+    if ("FAIL" in test_results_seen || "XPASS" in test_results_seen)
+      return "FAIL"
+    all_skipped = 1
+    for (k in test_results_seen)
+      if (k != "SKIP")
+        all_skipped = 0
+    if (all_skipped)
+      return "SKIP"
+    return "PASS";
+}
+
+function stringify_result_obj(result_obj)
+{
+  if (result_obj["is_unplanned"] || result_obj["number"] != testno)
+    return "ERROR"
+
+  if (plan_seen == LATE_PLAN)
+    return "ERROR"
+
+  if (result_obj["directive"] == "TODO")
+    return result_obj["is_ok"] ? "XPASS" : "XFAIL"
+
+  if (result_obj["directive"] == "SKIP")
+    return result_obj["is_ok"] ? "SKIP" : COOKED_FAIL;
+
+  if (length(result_obj["directive"]))
+      abort("in function stringify_result_obj()")
+
+  return result_obj["is_ok"] ? COOKED_PASS : COOKED_FAIL
+}
+
+function decorate_result(result)
+{
+  color_name = color_for_result[result]
+  if (color_name)
+    return color_map[color_name] "" result "" color_map["std"]
+  # If we are not using colorized output, or if we do not know how
+  # to colorize the given result, we should return it unchanged.
+  return result
+}
+
+function report(result, details)
+{
+  if (result ~ /^(X?(PASS|FAIL)|SKIP|ERROR)/)
+    {
+      msg = ": " test_script_name
+      add_test_result(result)
+    }
+  else if (result == "#")
+    {
+      msg = " " test_script_name ":"
+    }
+  else
+    {
+      abort("in function report()")
+    }
+  if (length(details))
+    msg = msg " " details
+  # Output on console might be colorized.
+  print decorate_result(result) msg
+  # Log the result in the log file too, to help debugging (this is
+  # especially true when said result is a TAP error or "Bail out!").
+  print result msg | "cat >&3";
+}
+
+function testsuite_error(error_message)
+{
+  report("ERROR", "- " error_message)
+}
+
+function handle_tap_result()
+{
+  details = result_obj["number"];
+  if (length(result_obj["description"]))
+    details = details " " result_obj["description"]
+
+  if (plan_seen == LATE_PLAN)
+    {
+      details = details " # AFTER LATE PLAN";
+    }
+  else if (result_obj["is_unplanned"])
+    {
+       details = details " # UNPLANNED";
+    }
+  else if (result_obj["number"] != testno)
+    {
+       details = sprintf("%s # OUT-OF-ORDER (expecting %d)",
+                         details, testno);
+    }
+  else if (result_obj["directive"])
+    {
+      details = details " # " result_obj["directive"];
+      if (length(result_obj["explanation"]))
+        details = details " " result_obj["explanation"]
+    }
+
+  report(stringify_result_obj(result_obj), details)
+}
+
+# `skip_reason` should be empty whenever planned > 0.
+function handle_tap_plan(planned, skip_reason)
+{
+  planned += 0 # Avoid getting confused if, say, `planned` is "00"
+  if (length(skip_reason) && planned > 0)
+    abort("in function handle_tap_plan()")
+  if (plan_seen)
+    {
+      # Error, only one plan per stream is acceptable.
+      testsuite_error("multiple test plans")
+      return;
+    }
+  planned_tests = planned
+  # The TAP plan can come before or after *all* the TAP results; we speak
+  # respectively of an "early" or a "late" plan.  If we see the plan line
+  # after at least one TAP result has been seen, assume we have a late
+  # plan; in this case, any further test result seen after the plan will
+  # be flagged as an error.
+  plan_seen = (testno >= 1 ? LATE_PLAN : EARLY_PLAN)
+  # If testno > 0, we have an error ("too many tests run") that will be
+  # automatically dealt with later, so do not worry about it here.  If
+  # $plan_seen is true, we have an error due to a repeated plan, and that
+  # has already been dealt with above.  Otherwise, we have a valid "plan
+  # with SKIP" specification, and should report it as a particular kind
+  # of SKIP result.
+  if (planned == 0 && testno == 0)
+    {
+      if (length(skip_reason))
+        skip_reason = "- "  skip_reason;
+      report("SKIP", skip_reason);
+    }
+}
+
+function extract_tap_comment(line)
+{
+  if (index(line, diag_string) == 1)
+    {
+      # Strip leading `diag_string` from `line`.
+      line = substr(line, length(diag_string) + 1)
+      # And strip any leading and trailing whitespace left.
+      sub("^[ \t]*", "", line)
+      sub("[ \t]*$", "", line)
+      # Return what is left (if any).
+      return line;
+    }
+  return "";
+}
+
+# When this function is called, we know that line is a TAP result line,
+# so that it matches the (perl) RE "^(not )?ok\b".
+function setup_result_obj(line)
+{
+  # Get the result, and remove it from the line.
+  result_obj["is_ok"] = (substr(line, 1, 2) == "ok" ? 1 : 0)
+  sub("^(not )?ok[ \t]*", "", line)
+
+  # If the result has an explicit number, get it and strip it; otherwise,
+  # automatically assing the next progresive number to it.
+  if (line ~ /^[0-9]+$/ || line ~ /^[0-9]+[^a-zA-Z0-9_]/)
+    {
+      match(line, "^[0-9]+")
+      # The final `+ 0` is to normalize numbers with leading zeros.
+      result_obj["number"] = substr(line, 1, RLENGTH) + 0
+      line = substr(line, RLENGTH + 1)
+    }
+  else
+    {
+      result_obj["number"] = testno
+    }
+
+  if (plan_seen == LATE_PLAN)
+    # No further test results are acceptable after a "late" TAP plan
+    # has been seen.
+    result_obj["is_unplanned"] = 1
+  else if (plan_seen && testno > planned_tests)
+    result_obj["is_unplanned"] = 1
+  else
+    result_obj["is_unplanned"] = 0
+
+  # Strip trailing and leading whitespace.
+  sub("^[ \t]*", "", line)
+  sub("[ \t]*$", "", line)
+
+  # This will have to be corrected if we have a "TODO"/"SKIP" directive.
+  result_obj["description"] = line
+  result_obj["directive"] = ""
+  result_obj["explanation"] = ""
+
+  if (index(line, "#") == 0)
+    return # No possible directive, nothing more to do.
+
+  # Directives are case-insensitive.
+  rx = "[ \t]*#[ \t]*([tT][oO][dD][oO]|[sS][kK][iI][pP])[ \t]*"
+
+  # See whether we have the directive, and if yes, where.
+  pos = match(line, rx "$")
+  if (!pos)
+    pos = match(line, rx "[^a-zA-Z0-9_]")
+
+  # If there was no TAP directive, we have nothing more to do.
+  if (!pos)
+    return
+
+  # Let`s now see if the TAP directive has been escaped.  For example:
+  #  escaped:     ok \# SKIP
+  #  not escaped: ok \\# SKIP
+  #  escaped:     ok \\\\\# SKIP
+  #  not escaped: ok \ # SKIP
+  if (substr(line, pos, 1) == "#")
+    {
+      bslash_count = 0
+      for (i = pos; i > 1 && substr(line, i - 1, 1) == "\\"; i--)
+        bslash_count += 1
+      if (bslash_count % 2)
+        return # Directive was escaped.
+    }
+
+  # Strip the directive and its explanation (if any) from the test
+  # description.
+  result_obj["description"] = substr(line, 1, pos - 1)
+  # Now remove the test description from the line, that has been dealt
+  # with already.
+  line = substr(line, pos)
+  # Strip the directive, and save its value (normalized to upper case).
+  sub("^[ \t]*#[ \t]*", "", line)
+  result_obj["directive"] = toupper(substr(line, 1, 4))
+  line = substr(line, 5)
+  # Now get the explanation for the directive (if any), with leading
+  # and trailing whitespace removed.
+  sub("^[ \t]*", "", line)
+  sub("[ \t]*$", "", line)
+  result_obj["explanation"] = line
+}
+
+function get_test_exit_message(status)
+{
+  if (status == 0)
+    return ""
+  if (status !~ /^[1-9][0-9]*$/)
+    abort("getting exit status")
+  if (status < 127)
+    exit_details = ""
+  else if (status == 127)
+    exit_details = " (command not found?)"
+  else if (status >= 128 && status <= 255)
+    exit_details = sprintf(" (terminated by signal %d?)", status - 128)
+  else if (status > 256 && status <= 384)
+    # We used to report an "abnormal termination" here, but some Korn
+    # shells, when a child process die due to signal number n, can leave
+    # in $? an exit status of 256+n instead of the more standard 128+n.
+    # Apparently, both behaviours are allowed by POSIX (2008), so be
+    # prepared to handle them both.  See also Austing Group report ID
+    # 0000051 <http://www.austingroupbugs.net/view.php?id=51>
+    exit_details = sprintf(" (terminated by signal %d?)", status - 256)
+  else
+    # Never seen in practice.
+    exit_details = " (abnormal termination)"
+  return sprintf("exited with status %d%s", status, exit_details)
+}
+
+function write_test_results()
+{
+  print ":global-test-result: " get_global_test_result() > trs_file
+  print ":recheck: "  yn(must_recheck()) > trs_file
+  print ":copy-in-global-log: " yn(copy_in_global_log()) > trs_file
+  for (i = 0; i < test_results_index; i += 1)
+    print ":test-result: " test_results_list[i] > trs_file
+  close(trs_file);
+}
+
+BEGIN {
+
+## ------- ##
+##  SETUP  ##
+## ------- ##
+
+'"$init_colors"'
+
+# Properly initialized once the TAP plan is seen.
+planned_tests = 0
+
+COOKED_PASS = expect_failure ? "XPASS": "PASS";
+COOKED_FAIL = expect_failure ? "XFAIL": "FAIL";
+
+# Enumeration-like constants to remember which kind of plan (if any)
+# has been seen.  It is important that NO_PLAN evaluates "false" as
+# a boolean.
+NO_PLAN = 0
+EARLY_PLAN = 1
+LATE_PLAN = 2
+
+testno = 0     # Number of test results seen so far.
+bailed_out = 0 # Whether a "Bail out!" directive has been seen.
+
+# Whether the TAP plan has been seen or not, and if yes, which kind
+# it is ("early" is seen before any test result, "late" otherwise).
+plan_seen = NO_PLAN
+
+## --------- ##
+##  PARSING  ##
+## --------- ##
+
+is_first_read = 1
+
+while (1)
+  {
+    # Involutions required so that we are able to read the exit status
+    # from the last input line.
+    st = getline
+    if (st < 0) # I/O error.
+      fatal("I/O error while reading from input stream")
+    else if (st == 0) # End-of-input
+      {
+        if (is_first_read)
+          abort("in input loop: only one input line")
+        break
+      }
+    if (is_first_read)
+      {
+        is_first_read = 0
+        nextline = $0
+        continue
+      }
+    else
+      {
+        curline = nextline
+        nextline = $0
+        $0 = curline
+      }
+    # Copy any input line verbatim into the log file.
+    print | "cat >&3"
+    # Parsing of TAP input should stop after a "Bail out!" directive.
+    if (bailed_out)
+      continue
+
+    # TAP test result.
+    if ($0 ~ /^(not )?ok$/ || $0 ~ /^(not )?ok[^a-zA-Z0-9_]/)
+      {
+        testno += 1
+        setup_result_obj($0)
+        handle_tap_result()
+      }
+    # TAP plan (normal or "SKIP" without explanation).
+    else if ($0 ~ /^1\.\.[0-9]+[ \t]*$/)
+      {
+        # The next two lines will put the number of planned tests in $0.
+        sub("^1\\.\\.", "")
+        sub("[^0-9]*$", "")
+        handle_tap_plan($0, "")
+        continue
+      }
+    # TAP "SKIP" plan, with an explanation.
+    else if ($0 ~ /^1\.\.0+[ \t]*#/)
+      {
+        # The next lines will put the skip explanation in $0, stripping
+        # any leading and trailing whitespace.  This is a little more
+        # tricky in truth, since we want to also strip a potential leading
+        # "SKIP" string from the message.
+        sub("^[^#]*#[ \t]*(SKIP[: \t][ \t]*)?", "")
+        sub("[ \t]*$", "");
+        handle_tap_plan(0, $0)
+      }
+    # "Bail out!" magic.
+    # Older versions of prove and TAP::Harness (e.g., 3.17) did not
+    # recognize a "Bail out!" directive when preceded by leading
+    # whitespace, but more modern versions (e.g., 3.23) do.  So we
+    # emulate the latter, "more modern" behaviour.
+    else if ($0 ~ /^[ \t]*Bail out!/)
+      {
+        bailed_out = 1
+        # Get the bailout message (if any), with leading and trailing
+        # whitespace stripped.  The message remains stored in `$0`.
+        sub("^[ \t]*Bail out![ \t]*", "");
+        sub("[ \t]*$", "");
+        # Format the error message for the
+        bailout_message = "Bail out!"
+        if (length($0))
+          bailout_message = bailout_message " " $0
+        testsuite_error(bailout_message)
+      }
+    # Maybe we have too look for dianogtic comments too.
+    else if (comments != 0)
+      {
+        comment = extract_tap_comment($0);
+        if (length(comment))
+          report("#", comment);
+      }
+  }
+
+## -------- ##
+##  FINISH  ##
+## -------- ##
+
+# A "Bail out!" directive should cause us to ignore any following TAP
+# error, as well as a non-zero exit status from the TAP producer.
+if (!bailed_out)
+  {
+    if (!plan_seen)
+      {
+        testsuite_error("missing test plan")
+      }
+    else if (planned_tests != testno)
+      {
+        bad_amount = testno > planned_tests ? "many" : "few"
+        testsuite_error(sprintf("too %s tests run (expected %d, got %d)",
+                                bad_amount, planned_tests, testno))
+      }
+    if (!ignore_exit)
+      {
+        # Fetch exit status from the last line.
+        exit_message = get_test_exit_message(nextline)
+        if (exit_message)
+          testsuite_error(exit_message)
+      }
+  }
+
+write_test_results()
+
+exit 0
+
+} # End of "BEGIN" block.
+'
+
+# TODO: document that we consume the file descriptor 3 :-(
+} 3>"$log_file"
+
+test $? -eq 0 || fatal "I/O or internal error"
+
+# Local Variables:
+# mode: shell-script
+# sh-indentation: 2
+# eval: (add-hook 'write-file-hooks 'time-stamp)
+# time-stamp-start: "scriptversion="
+# time-stamp-format: "%:y-%02m-%02d.%02H"
+# time-stamp-time-zone: "UTC"
+# time-stamp-end: "; # UTC"
+# End:
diff --git a/utils/tap-test b/utils/tap-test
new file mode 100755
index 00000000..481e333e
--- /dev/null
+++ b/utils/tap-test
@@ -0,0 +1,5 @@
+#! /bin/sh
+
+# run a GTest in tap mode. The test binary is passed as $1
+
+$1 -k --tap