diff --git a/docker/context/fish_run_tests.sh b/docker/context/fish_run_tests.sh
index 1b3d7894d..2adb0f21d 100755
--- a/docker/context/fish_run_tests.sh
+++ b/docker/context/fish_run_tests.sh
@@ -4,6 +4,7 @@
 # It is the entry point for running Docker-based tests.
 
 cd ~/fish-build
+git config --global --add safe.directory /fish-source
 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug /fish-source "$@"
 
 # Spawn a shell if FISH_RUN_SHELL_BEFORE_TESTS is set.