diff --git a/certlib/testdata/ec-ca.yaml b/certlib/testdata/ec-ca.yaml
index e9f0f45..2609b7c 100644
--- a/certlib/testdata/ec-ca.yaml
+++ b/certlib/testdata/ec-ca.yaml
@@ -9,5 +9,6 @@ subject:
 profile:
   is_ca: true
   path_len: 3
-  key_uses: cert sign
+  key_uses:
+    - cert sign
   expiry: 20y
diff --git a/certlib/testdata/rsa-ca.yaml b/certlib/testdata/rsa-ca.yaml
index 90c834a..5712ccf 100644
--- a/certlib/testdata/rsa-ca.yaml
+++ b/certlib/testdata/rsa-ca.yaml
@@ -9,5 +9,6 @@ subject:
 profile:
   is_ca: true
   path_len: 3
-  key_uses: cert sign
+  key_uses:
+    - cert sign
   expiry: 20y