diff --git a/t/lib-terminal.sh b/t/lib-terminal.sh
index cd220e378e..e3809dcead 100644
--- a/t/lib-terminal.sh
+++ b/t/lib-terminal.sh
@@ -9,8 +9,8 @@ test_terminal () {
 		echo >&4 "test_terminal: need to declare TTY prerequisite"
 		return 127
 	fi
-	perl "$TEST_DIRECTORY"/test-terminal.perl "$@"
-}
+	perl "$TEST_DIRECTORY"/test-terminal.perl "$@" 2>&7
+} 7>&2 2>&4
 
 test_lazy_prereq TTY '
 	test_have_prereq PERL &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 67b5994afb..37eb34044a 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -621,7 +621,7 @@ test_must_fail () {
 		_test_ok=
 		;;
 	esac
-	"$@"
+	"$@" 2>&7
 	exit_code=$?
 	if test $exit_code -eq 0 && ! list_contains "$_test_ok" success
 	then
@@ -644,7 +644,7 @@ test_must_fail () {
 		return 1
 	fi
 	return 0
-}
+} 7>&2 2>&4
 
 # Similar to test_must_fail, but tolerates success, too.  This is
 # meant to be used in contexts like:
@@ -658,8 +658,8 @@ test_must_fail () {
 # because we want to notice if it fails due to segv.
 
 test_might_fail () {
-	test_must_fail ok=success "$@"
-}
+	test_must_fail ok=success "$@" 2>&7
+} 7>&2 2>&4
 
 # Similar to test_must_fail and test_might_fail, but check that a
 # given command exited with a given exit code. Meant to be used as:
@@ -671,7 +671,7 @@ test_might_fail () {
 test_expect_code () {
 	want_code=$1
 	shift
-	"$@"
+	"$@" 2>&7
 	exit_code=$?
 	if test $exit_code = $want_code
 	then
@@ -680,7 +680,7 @@ test_expect_code () {
 
 	echo >&2 "test_expect_code: command exited with $exit_code, we wanted $want_code $*"
 	return 1
-}
+} 7>&2 2>&4
 
 # test_cmp is a helper function to compare actual and expected output.
 # You can use it like:
@@ -882,8 +882,8 @@ test_write_lines () {
 }
 
 perl () {
-	command "$PERL_PATH" "$@"
-}
+	command "$PERL_PATH" "$@" 2>&7
+} 7>&2 2>&4
 
 # Is the value one of the various ways to spell a boolean true/false?
 test_normalize_bool () {
@@ -1023,13 +1023,13 @@ test_env () {
 				shift
 				;;
 			*)
-				"$@"
+				"$@" 2>&7
 				exit
 				;;
 			esac
 		done
 	)
-}
+} 7>&2 2>&4
 
 # Returns true if the numeric exit code in "$2" represents the expected signal
 # in "$1". Signals should be given numerically.
@@ -1071,9 +1071,9 @@ nongit () {
 		GIT_CEILING_DIRECTORIES=$(pwd) &&
 		export GIT_CEILING_DIRECTORIES &&
 		cd non-repo &&
-		"$@"
+		"$@" 2>&7
 	)
-}
+} 7>&2 2>&4
 
 # convert stdin to pktline representation; note that empty input becomes an
 # empty packet, not a flush packet (for that you can just print 0000 yourself).