tests: add 'test_bool_env' to catch non-bool GIT_TEST_* values

Since 3b072c577b (tests: replace test_tristate with "git env--helper",
2019-06-21) we get the normalized bool values of various GIT_TEST_*
environment variables via 'git env--helper'.  Now, while the 'git
env--helper' command itself does catch invalid values in the
environment variable or in the given --default and exits with error
(exit code 128 or 129, respectively), it's invoked in conditions like
'if ! git env--helper ...', which means that all invalid bool values
are interpreted the same as the ordinary 'false' (exit code 1).  This
has led to inadvertently skipped httpd tests in our CI builds for a
couple of weeks, see 3960290675 (ci: restore running httpd tests,
2019-09-06).

Let's be more careful about what the test suite accepts as bool values
in GIT_TEST_* environment variables, and error out loud and clear on
invalid values instead of simply skipping tests.  Add the
'test_bool_env' helper function to encapsulate the invocation of 'git
env--helper' and the verification of its exit code, and replace all
invocations of that command in our test framework and test suite with
a call to this new helper (except in 't0017-env-helper.sh', of
course).

  $ GIT_TEST_GIT_DAEMON=YesPlease ./t5570-git-daemon.sh
  fatal: bad numeric config value 'YesPlease' for 'GIT_TEST_GIT_DAEMON': invalid unit
  error: test_bool_env requires bool values both for $GIT_TEST_GIT_DAEMON and for the default fallback

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index b299ecc326..5136a6724a 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -1175,6 +1175,34 @@ perl () {
 	command "$PERL_PATH" "$@" 2>&7
 } 7>&2 2>&4
 
+# Given the name of an environment variable with a bool value, normalize
+# its value to a 0 (true) or 1 (false or empty string) return code.
+#
+#   test_bool_env GIT_TEST_HTTPD <default-value>
+#
+# Return with code corresponding to the given default value if the variable
+# is unset.
+# Abort the test script if either the value of the variable or the default
+# are not valid bool values.
+
+test_bool_env () {
+	if test $# != 2
+	then
+		BUG "test_bool_env requires two parameters (variable name and default value)"
+	fi
+
+	git env--helper --type=bool --default="$2" --exit-code "$1"
+	ret=$?
+	case $ret in
+	0|1)	# unset or valid bool value
+		;;
+	*)	# invalid bool value or something unexpected
+		error >&7 "test_bool_env requires bool values both for \$$1 and for the default fallback"
+		;;
+	esac
+	return $ret
+}
+
 # Exit the test suite, either by skipping all remaining tests or by
 # exiting with an error. If our prerequisite variable $1 falls back
 # on a default assume we were opportunistically trying to set up some
@@ -1183,7 +1211,7 @@ perl () {
 # The error/skip message should be given by $2.
 #
 test_skip_or_die () {
-	if ! git env--helper --type=bool --default=false --exit-code $1
+	if ! test_bool_env "$1" false
 	then
 		skip_all=$2
 		test_done