diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 93c03380d4..af4831a54c 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -795,7 +795,7 @@ test_verify_prereq () {
 }
 
 test_expect_failure () {
-	test_start_
+	test_start_ "$@"
 	test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
 	test "$#" = 2 ||
 	BUG "not 2 or 3 parameters to test-expect-failure"
@@ -815,7 +815,7 @@ test_expect_failure () {
 }
 
 test_expect_success () {
-	test_start_
+	test_start_ "$@"
 	test "$#" = 3 && { test_prereq=$1; shift; } || test_prereq=
 	test "$#" = 2 ||
 	BUG "not 2 or 3 parameters to test-expect-success"
diff --git a/t/test-lib-github-workflow-markup.sh b/t/test-lib-github-workflow-markup.sh
new file mode 100644
index 0000000000..d8dc969df4
--- /dev/null
+++ b/t/test-lib-github-workflow-markup.sh
@@ -0,0 +1,50 @@
+# Library of functions to mark up test scripts' output suitable for
+# pretty-printing it in GitHub workflows.
+#
+# Copyright (c) 2022 Johannes Schindelin
+#
+# 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 of the License, 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/ .
+#
+# The idea is for `test-lib.sh` to source this file when run in GitHub
+# workflows; these functions will then override (empty) functions
+# that are are called at the appropriate times during the test runs.
+
+start_test_output () {
+	test -n "$GIT_TEST_TEE_OUTPUT_FILE" ||
+	die "--github-workflow-markup requires --verbose-log"
+	github_markup_output="${GIT_TEST_TEE_OUTPUT_FILE%.out}.markup"
+	>$github_markup_output
+	GIT_TEST_TEE_OFFSET=0
+}
+
+# No need to override start_test_case_output
+
+finalize_test_case_output () {
+	test_case_result=$1
+	shift
+	case "$test_case_result" in
+	failure)
+		echo >>$github_markup_output "::error::failed: $this_test.$test_count $1"
+		;;
+	fixed)
+		echo >>$github_markup_output "::notice::fixed: $this_test.$test_count $1"
+		;;
+	esac
+	echo >>$github_markup_output "::group::$test_case_result: $this_test.$test_count $*"
+	test-tool >>$github_markup_output path-utils skip-n-bytes \
+		"$GIT_TEST_TEE_OUTPUT_FILE" $GIT_TEST_TEE_OFFSET
+	echo >>$github_markup_output "::endgroup::"
+}
+
+# No need to override finalize_test_output
diff --git a/t/test-lib.sh b/t/test-lib.sh
index bdb11e28ee..29640d107c 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -204,6 +204,9 @@ parse_option () {
 	--write-junit-xml)
 		. "$TEST_DIRECTORY/test-lib-junit.sh"
 		;;
+	--github-workflow-markup)
+		. "$TEST_DIRECTORY/test-lib-github-workflow-markup.sh"
+		;;
 	--stress)
 		stress=t ;;
 	--stress=*)
@@ -1082,7 +1085,7 @@ test_start_ () {
 	test_count=$(($test_count+1))
 	maybe_setup_verbose
 	maybe_setup_valgrind
-	start_test_case_output
+	start_test_case_output "$@"
 }
 
 test_finish_ () {