Fixes #1026.

vunit/configuration.py

@@ -258,6 +258,24 @@ def set_post_check(self, value):
             for config in configs.values():
                 config.post_check = value
 
+    @staticmethod
+    def _check_architectures(design_unit):
+        """
+        Check that an entity which has been classified as a VUnit test bench
+        has exactly one architecture. Raise RuntimeError otherwise.
+        """
+        if design_unit.is_entity:
+            if not design_unit.architecture_names:
+                raise RuntimeError(f"Test bench '{design_unit.name!s}' has no architecture.")
+
+            if len(design_unit.architecture_names) > 1:
+                archs = ", ".join(
+                    f"{name!s}:{Path(fname).name!s}" for name, fname in sorted(design_unit.architecture_names.items())
+                )
+                raise RuntimeError(
+                    "Test bench not allowed to have multiple architectures. " f"Entity {design_unit.name!s} has {archs}"
+                )
+
     def add_config(  # pylint: disable=too-many-arguments
         self,
         name,
@@ -276,6 +294,8 @@ def add_config(  # pylint: disable=too-many-arguments
         if name in (DEFAULT_NAME, ""):
             raise ValueError(f"Illegal configuration name {name!r}. Must be non-empty string")
 
+        self._check_architectures(self.design_unit)
+
         for configs in self.get_configuration_dicts():
             if name in configs:
                 raise RuntimeError(f"Configuration name {name!s} already defined")

vunit/test/bench.py

@@ -76,24 +76,6 @@ def get_default_config(self):
             raise RuntimeError(f"Test bench {self.library_name!s}.{self.name!s} has individually configured tests")
         return self._configs[DEFAULT_NAME]
 
-    @staticmethod
-    def _check_architectures(design_unit):
-        """
-        Check that an entity which has been classified as a VUnit test bench
-        has exactly one architecture. Raise RuntimeError otherwise.
-        """
-        if design_unit.is_entity:
-            if not design_unit.architecture_names:
-                raise RuntimeError(f"Test bench '{design_unit.name!s}' has no architecture.")
-
-            if len(design_unit.architecture_names) > 1:
-                archs = ", ".join(
-                    f"{name!s}:{Path(fname).name!s}" for name, fname in sorted(design_unit.architecture_names.items())
-                )
-                raise RuntimeError(
-                    "Test bench not allowed to have multiple architectures. " f"Entity {design_unit.name!s} has {archs}"
-                )
-
     def create_tests(self, simulator_if, elaborate_only, test_list=None):
         """
         Create all test cases from this test bench