Fix to be more genral

Signed-off-by: elronbandel <elronbandel@gmail.com>

src/unitxt/standard.py

@@ -413,10 +413,15 @@ def prepare(self):
         ), f"Specify either template ({self.template}) or template_card_index ({self.template_card_index}) but not both"
 
         if self.template_card_index is None and self.template is None:
-            self.template_card_index = 0
-            logger.warning(
-                "Template was not specified in recipe, using template_card_index=0 by default."
-            )
+            if self.card is not None:
+                self.template_card_index = next(iter(self.card.templates))
+                logger.warning(
+                    "Template was not specified in recipe, using the first template from the card by default."
+                )
+            else:
+                raise ValueError(
+                    "Specify a template or template_card_index, or a card to get a default template from."
+                )
 
         if self.template_card_index is not None:
             try:

tests/library/test_recipe.py

@@ -554,13 +554,6 @@ def test_standard_recipe_with_no_test(self):
         self.assertTrue(len(results) > 0)
 
     def test_standard_recipe_with_template_errors(self):
-        # Check some template was specified
-        with self.assertRaises(AssertionError) as cm:
-            StandardRecipeWithIndexes(card="cards.wnli")
-        self.assertEqual(
-            str(cm.exception), "Specify either template or template_card_index in card"
-        )
-
         # Check either template or template index was specified , but not both
         with self.assertRaises(AssertionError) as cm:
             StandardRecipeWithIndexes(