diff --git a/tests/config_ini/incomplete.ini b/tests/config_ini/incomplete.ini
new file mode 100644
index 0000000000000000000000000000000000000000..7fc7852b490fdb6ab6c30c169b17f396d7a5e298
--- /dev/null
+++ b/tests/config_ini/incomplete.ini
@@ -0,0 +1,9 @@
+[Cache]
+# No directory.
+# FIXME: Write pattern-validating code, and then make this the section:
+# directory = /tmp
+# historical = rates.json
+
+[OXR]
+# No app_id.
+api_root = http://[100::]/oxrlibtest/