diff --git a/scripts/run_cached_tests b/scripts/run_cached_tests
index c6add9a..048bfbb 100755
--- a/scripts/run_cached_tests
+++ b/scripts/run_cached_tests
@@ -12,6 +12,13 @@ if [[ -f keyfile.toml ]]; then
   export KEYFILE=keyfile.toml
 fi
 
+for _ in {1..10}; do
+  if [[ -s ~/.mitmproxy/mitmproxy-ca-cert.pem ]]; then
+    break
+  fi
+  sleep 1
+done
+
 http_proxy=http://localhost:7890 https_proxy=http://localhost:7890 FAKEROOTDONTTRYCHOWN=1 bwrap --dev-bind / / --bind ~/.mitmproxy/mitmproxy-ca-cert.pem /etc/ssl/cert.pem pytest
 
 kill -INT $mitm_pid