diff --git a/tests/features/step_definitions/gitops-update.steps.js b/tests/features/step_definitions/gitops-update.steps.js
index 4a033ba..b0009f2 100644
--- a/tests/features/step_definitions/gitops-update.steps.js
+++ b/tests/features/step_definitions/gitops-update.steps.js
@@ -74,7 +74,7 @@ function requestCount() {
 }
 
 function gitCalls() {
-  const out = bash(`cat "${GIT_CALLS_FILE:-/dev/null}" 2>/dev/null || echo ""`).stdout;
+  const out = bash(`cat "${GIT_CALLS_FILE || '/dev/null'}" 2>/dev/null || echo ""`).stdout;
   return out.split('\n').filter(l => l.length > 0);
 }