diff --git a/tests/unit/render/test_vega_converter.py b/tests/unit/render/test_vega_converter.py
index 7f3c85479..64179279d 100644
--- a/tests/unit/render/test_vega_converter.py
+++ b/tests/unit/render/test_vega_converter.py
@@ -258,6 +258,10 @@ def test_convert(
             {"x": {"train_actual.csv": "actual", "val_actual.csv": "actual"}},
             "actual",
         ),
+        (
+            {"x": {"actual.csv": "actual", "predicted.csv": "predicted"}},
+            "x",
+        ),
     ],
 )
 def test_infer_x_label(properties, label):