diff --git a/tests/test_pyroc.py b/tests/test_pyroc.py
index f3a9f14..a4e1687 100644
--- a/tests/test_pyroc.py
+++ b/tests/test_pyroc.py
@@ -36,6 +36,16 @@ def test_pyroc_input_parsing(ovarian_cancer_dataset):
     target = df['outcome'].values
     df = df.drop('outcome', axis=1)
 
+    # single numpy array of preds
+    preds = df['albumin'].values
+    roc = pyroc.ROC(
+        target,
+        preds,
+    )
+    # since roc wasn't provided predictor labels,
+    # keys are integers (i)
+    assert (roc.preds[0][:n] == expected_values['albumin'][:n]).all()
+
     # numpy arrays
     preds = df.values
     roc = pyroc.ROC(