diff --git a/t/README b/t/README
index 7a3d582267..0b03175c7d 100644
--- a/t/README
+++ b/t/README
@@ -862,6 +862,26 @@ library for your script to use.
 		...
 	'
 
+ - test_atexit <script>
+
+   Prepend <script> to a list of commands to run unconditionally to
+   clean up before the test script exits, e.g. to stop a daemon:
+
+	test_expect_success 'test git daemon' '
+		git daemon &
+		daemon_pid=$! &&
+		test_atexit 'kill $daemon_pid' &&
+		hello world
+	'
+
+   The commands will be executed before the trash directory is removed,
+   i.e. the atexit commands will still be able to access any pidfiles or
+   socket files.
+
+   Note that these commands will be run even when a test script run
+   with '--immediate' fails.  Be careful with your atexit commands to
+   minimize any changes to the failed state.
+
  - test_write_lines <lines>
 
    Write <lines> on standard output, one line per argument.
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index b6566003dd..c03054c538 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -825,6 +825,24 @@ test_expect_success 'tests clean up even on failures' "
 	EOF
 "
 
+test_expect_success 'test_atexit is run' "
+	test_must_fail run_sub_test_lib_test \
+		atexit-cleanup 'Run atexit commands' -i <<-\\EOF &&
+	test_expect_success 'tests clean up even after a failure' '
+		> ../../clean-atexit &&
+		test_atexit rm ../../clean-atexit &&
+		> ../../also-clean-atexit &&
+		test_atexit rm ../../also-clean-atexit &&
+		> ../../dont-clean-atexit &&
+		(exit 1)
+	'
+	test_done
+	EOF
+	test_path_is_file dont-clean-atexit &&
+	test_path_is_missing clean-atexit &&
+	test_path_is_missing also-clean-atexit
+"
+
 test_expect_success 'test_oid setup' '
 	test_oid_init
 '
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 80402a428f..6a50dba390 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -934,6 +934,34 @@ test_when_finished () {
 		} && (exit \"\$eval_ret\"); eval_ret=\$?; $test_cleanup"
 }
 
+# This function can be used to schedule some commands to be run
+# unconditionally at the end of the test script, e.g. to stop a daemon:
+#
+#	test_expect_success 'test git daemon' '
+#		git daemon &
+#		daemon_pid=$! &&
+#		test_atexit 'kill $daemon_pid' &&
+#		hello world
+#	'
+#
+# The commands will be executed before the trash directory is removed,
+# i.e. the atexit commands will still be able to access any pidfiles or
+# socket files.
+#
+# Note that these commands will be run even when a test script run
+# with '--immediate' fails.  Be careful with your atexit commands to
+# minimize any changes to the failed state.
+
+test_atexit () {
+	# We cannot detect when we are in a subshell in general, but by
+	# doing so on Bash is better than nothing (the test will
+	# silently pass on other shells).
+	test "${BASH_SUBSHELL-0}" = 0 ||
+	error "bug in test script: test_atexit does nothing in a subshell"
+	test_atexit_cleanup="{ $*
+		} && (exit \"\$eval_ret\"); eval_ret=\$?; $test_atexit_cleanup"
+}
+
 # Most tests can use the created repository, but some may need to create more.
 # Usage: test_create_repo <directory>
 test_create_repo () {
diff --git a/t/test-lib.sh b/t/test-lib.sh
index ab3de007e2..ac3df9efd4 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -620,6 +620,10 @@ test_external_has_tap=0
 
 die () {
 	code=$?
+	# This is responsible for running the atexit commands even when a
+	# test script run with '--immediate' fails, or when the user hits
+	# ctrl-C, i.e. when 'test_done' is not invoked at all.
+	test_atexit_handler || code=$?
 	if test -n "$GIT_EXIT_OK"
 	then
 		exit $code
@@ -1045,9 +1049,28 @@ write_junit_xml_testcase () {
 	junit_have_testcase=t
 }
 
+test_atexit_cleanup=:
+test_atexit_handler () {
+	# In a succeeding test script 'test_atexit_handler' is invoked
+	# twice: first from 'test_done', then from 'die' in the trap on
+	# EXIT.
+	# This condition and resetting 'test_atexit_cleanup' below makes
+	# sure that the registered cleanup commands are run only once.
+	test : != "$test_atexit_cleanup" || return 0
+
+	setup_malloc_check
+	test_eval_ "$test_atexit_cleanup"
+	test_atexit_cleanup=:
+	teardown_malloc_check
+}
+
 test_done () {
 	GIT_EXIT_OK=t
 
+	# Run the atexit commands _before_ the trash directory is
+	# removed, so the commands can access pidfiles and socket files.
+	test_atexit_handler
+
 	if test -n "$write_junit_xml" && test -n "$junit_xml_path"
 	then
 		test -n "$junit_have_testcase" || {