Revert "Remove unused test data files"

This reverts commit ef24980e667debd0cb8f1f26218c452bacbbe084.
diff --git a/tests/data_files/cli.opensslconf b/tests/data_files/cli.opensslconf
new file mode 100644
index 0000000..ae9ab9d
--- /dev/null
+++ b/tests/data_files/cli.opensslconf
@@ -0,0 +1,4 @@
+[cli-rsa]
+subjectKeyIdentifier=hash
+authorityKeyIdentifier=keyid:always,issuer:always
+basicConstraints = CA:false