diff --git a/run-command.c b/run-command.c
index e3e02475cc..438a290d30 100644
--- a/run-command.c
+++ b/run-command.c
@@ -1828,7 +1828,7 @@ int prepare_auto_maintenance(int quiet, struct child_process *maint)
 	 */
 	if (repo_config_get_bool(the_repository, "maintenance.autodetach", &auto_detach) &&
 	    repo_config_get_bool(the_repository, "gc.autodetach", &auto_detach))
-		auto_detach = 1;
+		auto_detach = git_env_bool("GIT_TEST_MAINT_AUTO_DETACH", true);
 
 	maint->git_cmd = 1;
 	maint->close_object_store = 1;
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 1e354e057f..d62760eb92 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -229,7 +229,7 @@ test_expect_success 'fetch --refetch triggers repacking' '
 
 	GIT_TRACE2_EVENT="$PWD/trace1.event" \
 	git -C pc1 fetch --refetch origin &&
-	test_subcommand git maintenance run --auto --no-quiet --detach <trace1.event &&
+	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace1.event &&
 	grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace1.event &&
 	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace1.event &&
 
@@ -238,7 +238,7 @@ test_expect_success 'fetch --refetch triggers repacking' '
 		-c gc.autoPackLimit=0 \
 		-c maintenance.incremental-repack.auto=1234 \
 		-C pc1 fetch --refetch origin &&
-	test_subcommand git maintenance run --auto --no-quiet --detach <trace2.event &&
+	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace2.event &&
 	grep \"param\":\"gc.autopacklimit\",\"value\":\"0\" trace2.event &&
 	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"-1\" trace2.event &&
 
@@ -247,7 +247,7 @@ test_expect_success 'fetch --refetch triggers repacking' '
 		-c gc.autoPackLimit=1234 \
 		-c maintenance.incremental-repack.auto=0 \
 		-C pc1 fetch --refetch origin &&
-	test_subcommand git maintenance run --auto --no-quiet --detach <trace3.event &&
+	test_subcommand git maintenance run --auto --no-quiet --no-detach <trace3.event &&
 	grep \"param\":\"gc.autopacklimit\",\"value\":\"1\" trace3.event &&
 	grep \"param\":\"maintenance.incremental-repack.auto\",\"value\":\"0\" trace3.event
 '
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 7cc0ce57f8..fe344f47ee 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -7,6 +7,9 @@ test_description='git maintenance builtin'
 GIT_TEST_COMMIT_GRAPH=0
 GIT_TEST_MULTI_PACK_INDEX=0
 
+# Ensure that auto-maintenance detaches as usual.
+sane_unset GIT_TEST_MAINT_AUTO_DETACH
+
 test_lazy_prereq XMLLINT '
 	xmllint --version
 '
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 0fb76f7d11..aa805a01ce 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1947,6 +1947,10 @@ test_lazy_prereq COMPAT_HASH '
 GIT_TEST_MAINT_SCHEDULER="none:exit 1"
 export GIT_TEST_MAINT_SCHEDULER
 
+# Ensure that tests cannot race with background maintenance by default.
+GIT_TEST_MAINT_AUTO_DETACH="false"
+export GIT_TEST_MAINT_AUTO_DETACH
+
 # Does this platform support `git fsmonitor--daemon`
 #
 test_lazy_prereq FSMONITOR_DAEMON '