diff --git a/t/lib-git-daemon.sh b/t/lib-git-daemon.sh
index 1f22de260a..bc4b3412fb 100644
--- a/t/lib-git-daemon.sh
+++ b/t/lib-git-daemon.sh
@@ -16,9 +16,10 @@
 #	stop_git_daemon
 #	test_done
 
-if test -z "$GIT_TEST_GIT_DAEMON"
+test_tristate GIT_TEST_GIT_DAEMON
+if test "$GIT_TEST_GIT_DAEMON" = false
 then
-	skip_all="git-daemon testing disabled (define GIT_TEST_GIT_DAEMON to enable)"
+	skip_all="git-daemon testing disabled (unset GIT_TEST_GIT_DAEMON to enable)"
 	test_done
 fi
 
@@ -58,7 +59,8 @@ start_git_daemon() {
 		kill "$GIT_DAEMON_PID"
 		wait "$GIT_DAEMON_PID"
 		trap 'die' EXIT
-		error "git daemon failed to start"
+		test_skip_or_die $GIT_TEST_GIT_DAEMON \
+			"git daemon failed to start"
 	fi
 }
 
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index b43162ea2a..252cbf163b 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -30,9 +30,10 @@
 # Copyright (c) 2008 Clemens Buchacher <drizzd@aon.at>
 #
 
-if test -z "$GIT_TEST_HTTPD"
+test_tristate GIT_TEST_HTTPD
+if test "$GIT_TEST_HTTPD" = false
 then
-	skip_all="Network testing disabled (define GIT_TEST_HTTPD to enable)"
+	skip_all="Network testing disabled (unset GIT_TEST_HTTPD to enable)"
 	test_done
 fi
 
@@ -76,8 +77,7 @@ GIT_VALGRIND_OPTIONS=$GIT_VALGRIND_OPTIONS; export GIT_VALGRIND_OPTIONS
 
 if ! test -x "$LIB_HTTPD_PATH"
 then
-	skip_all="skipping test, no web server found at '$LIB_HTTPD_PATH'"
-	test_done
+	test_skip_or_die $GIT_TEST_HTTPD "no web server found at '$LIB_HTTPD_PATH'"
 fi
 
 HTTPD_VERSION=`$LIB_HTTPD_PATH -v | \
@@ -89,19 +89,20 @@ then
 	then
 		if ! test $HTTPD_VERSION -ge 2
 		then
-			skip_all="skipping test, at least Apache version 2 is required"
-			test_done
+			test_skip_or_die $GIT_TEST_HTTPD \
+				"at least Apache version 2 is required"
 		fi
 		if ! test -d "$DEFAULT_HTTPD_MODULE_PATH"
 		then
-			skip_all="Apache module directory not found.  Skipping tests."
-			test_done
+			test_skip_or_die $GIT_TEST_HTTPD \
+				"Apache module directory not found"
 		fi
 
 		LIB_HTTPD_MODULE_PATH="$DEFAULT_HTTPD_MODULE_PATH"
 	fi
 else
-	error "Could not identify web server at '$LIB_HTTPD_PATH'"
+	test_skip_or_die $GIT_TEST_HTTPD \
+		"Could not identify web server at '$LIB_HTTPD_PATH'"
 fi
 
 prepare_httpd() {
@@ -155,9 +156,8 @@ start_httpd() {
 		>&3 2>&4
 	if test $? -ne 0
 	then
-		skip_all="skipping test, web server setup failed"
 		trap 'die' EXIT
-		test_done
+		test_skip_or_die $GIT_TEST_HTTPD "web server setup failed"
 	fi
 }
 
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index aeae3ca769..b333e3ff86 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -716,6 +716,64 @@ perl () {
 	command "$PERL_PATH" "$@"
 }
 
+# Is the value one of the various ways to spell a boolean true/false?
+test_normalize_bool () {
+	git -c magic.variable="$1" config --bool magic.variable 2>/dev/null
+}
+
+# Given a variable $1, normalize the value of it to one of "true",
+# "false", or "auto" and store the result to it.
+#
+#     test_tristate GIT_TEST_HTTPD
+#
+# A variable set to an empty string is set to 'false'.
+# A variable set to 'false' or 'auto' keeps its value.
+# Anything else is set to 'true'.
+# An unset variable defaults to 'auto'.
+#
+# The last rule is to allow people to set the variable to an empty
+# string and export it to decline testing the particular feature
+# for versions both before and after this change.  We used to treat
+# both unset and empty variable as a signal for "do not test" and
+# took any non-empty string as "please test".
+
+test_tristate () {
+	if eval "test x\"\${$1+isset}\" = xisset"
+	then
+		# explicitly set
+		eval "
+			case \"\$$1\" in
+			'')	$1=false ;;
+			auto)	;;
+			*)	$1=\$(test_normalize_bool \$$1 || echo true) ;;
+			esac
+		"
+	else
+		eval "$1=auto"
+	fi
+}
+
+# Exit the test suite, either by skipping all remaining tests or by
+# exiting with an error. If "$1" is "auto", we then we assume we were
+# opportunistically trying to set up some tests and we skip. If it is
+# "true", then we report a failure.
+#
+# The error/skip message should be given by $2.
+#
+test_skip_or_die () {
+	case "$1" in
+	auto)
+		skip_all=$2
+		test_done
+		;;
+	true)
+		error "$2"
+		;;
+	*)
+		error "BUG: test tristate is '$1' (real error: $2)"
+	esac
+}
+
 # The following mingw_* functions obey POSIX shell syntax, but are actually
 # bash scripts, and are meant to be used only with bash on Windows.