validation: Improve no default entry error message

2 files changed, 21 insertions, 2 deletions

diff --git a/rtemsspec/tests/test_validation.py b/rtemsspec/tests/test_validation.py
index 71490a14..8902f530 100644
--- a/rtemsspec/tests/test_validation.py
+++ b/rtemsspec/tests/test_validation.py
@@ -2122,3 +2122,18 @@ def test_validation_invalid_actions():
              "set {A=A0} defined by transition map entry 0")
     with pytest.raises(ValueError, match=match):
         generate(validation_config, item_cache)
+    action_data["transition-map"][1]["pre-conditions"]["A"] = ["A1"]
+    action_data["pre-conditions"][0]["states"].append({
+        "name": "A1",
+        "test-code": None,
+        "text": None
+    })
+    action_data["pre-conditions"][0]["states"].append({
+        "name": "A2",
+        "test-code": None,
+        "text": None
+    })
+    match = ("transition map of spec:/a contains no default entry "
+             "for pre-condition set {A=A2}")
+    with pytest.raises(ValueError, match=match):
+        generate(validation_config, item_cache)
diff --git a/rtemsspec/validation.py b/rtemsspec/validation.py
index a1db8736..7e90b458 100644
--- a/rtemsspec/validation.py
+++ b/rtemsspec/validation.py
@@ -602,8 +602,12 @@ class _ActionRequirementTestItem(_TestItem):
         ])
         map_elements = []
         info_elements = []
-        for transistions in transition_map:
-            assert transistions[0].enabled_by == "1"
+        for map_index, transistions in enumerate(transition_map):
+            if not transistions or transistions[0].enabled_by != "1":
+                raise ValueError(
+                    f"transition map of {self.item.spec} contains no default "
+                    "entry for pre-condition set "
+                    f"{{{self._map_index_to_pre_conditions(map_index)}}}")
             if len(transistions) == 1:
                 map_elements.append(
                     self._post_condition_enumerators(