fix tabular in the presence of units

Author: nden

astropy/modeling/tabular.py

@@ -244,11 +244,11 @@ def evaluate(self, *inputs):
             bounds_error=self.bounds_error,
             fill_value=self.fill_value,
         )
-
+        
         # return_units not respected when points has no units
         if isinstance(self.lookup_table, u.Quantity) and not isinstance(
-            self.points[0], u.Quantity
-        ):
+            result, u.Quantity
+            ):
             result = result * self.lookup_table.unit
 
         if self.n_outputs == 1:

astropy/modeling/tests/test_models.py

@@ -729,6 +729,12 @@ def test_tabular_interp_1d():
     assert_quantity_allclose(model(xnew.to(u.nm)), ans1)
     assert model.bounding_box == (0 * u.nm, 4 * u.nm)
 
+    # Test with no units on points.
+    model = LookupTable(points=points, lookup_table=values * u.nJy)
+    assert_quantity_allclose(model(xnew), ans1)
+    assert_quantity_allclose(model(xnew.to(u.nm)), ans1)
+    assert model.bounding_box == (0 * u.nm, 4 * u.nm)
+
     # Test fill value unit conversion and unitless input on table with unit
     model = LookupTable(
         [1, 2, 3],