diff --git a/src/util/test_helper_eddsa.conf b/src/util/test_helper_eddsa.conf
index 321fa7cc3..8fe119c40 100644
--- a/src/util/test_helper_eddsa.conf
+++ b/src/util/test_helper_eddsa.conf
@@ -4,6 +4,7 @@ TALER_TEST_HOME = test_helper_eddsa_home/
 TALER_RUNTIME_DIR = ${TMPDIR:-/tmp}/${USER}/test_helper_eddsa/
 
 [taler-exchange-secmod-eddsa]
+CLIENT_DIR = $TALER_RUNTIME_DIR
 LOOKAHEAD_SIGN = 5 minutes
 OVERLAP_DURATION = 1 s
 DURATION = 1 minute