fix: validate scorer instance names in config (#407)

* fix: validate scorer instance names in config

* fix: run scorer config tests in CI

* fix: drop redundant UV_PYTHON env and quote unittest pattern

* fix: report precise scorer name validation errors

.github/workflows/ci.yml

@@ -43,7 +43,9 @@ jobs:
       - name: Run tests
         env:
           PYTHONUNBUFFERED: "1"
-        run: uv run tests/run_tests.py 2>&1
+        run: |
+          uv run python -m unittest discover -s tests -p 'test_*.py'
+          uv run tests/run_tests.py 2>&1
 
       - name: Build package
         run: uv build

src/heretic/config.py

@@ -9,6 +9,7 @@ from pydantic import (
     Field,
     NonNegativeInt,
     PositiveInt,
+    field_validator,
 )
 from pydantic_settings import (
     BaseSettings,
@@ -123,6 +124,23 @@ class ScorerConfig(BaseModel):
         ),
     )
 
+    @field_validator("instance_name")
+    @classmethod
+    def validate_instance_name(cls, value: str | None) -> str | None:
+        if value is None:
+            return value
+
+        if not value.strip():
+            raise ValueError("cannot be empty or whitespace")
+
+        if "." in value:
+            raise ValueError("'.' is not allowed")
+
+        if any(char.isspace() for char in value):
+            raise ValueError("whitespace is not allowed")
+
+        return value
+
 
 class BenchmarkSpecification(BaseModel):
     task: str = Field(

src/heretic/evaluator.py

@@ -67,18 +67,6 @@ class Evaluator:
             # Instantiate scorers.
             instance_name = config.instance_name or None
 
-            if instance_name is not None:
-                if not instance_name.strip():
-                    raise ValueError(
-                        f"Invalid instance_name {instance_name} for scorer {scorer_cls.__name__}: "
-                        "cannot be empty or whitespace"
-                    )
-                if "." in instance_name or " " in instance_name:
-                    raise ValueError(
-                        f"Invalid instance_name {instance_name} for scorer {scorer_cls.__name__}: "
-                        "'.' and whitespace are not allowed"
-                    )
-
             raw_settings = self._get_scorer_settings_raw(
                 scorer_cls=scorer_cls, instance_name=instance_name
             )

tests/test_config.py

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# Copyright (C) 2025-2026  Philipp Emanuel Weidmann <pew@worldwidemann.com> + contributors
+
+import unittest
+
+from pydantic import ValidationError
+
+from heretic.config import ScorerConfig
+
+
+class ScorerConfigTests(unittest.TestCase):
+    def test_accepts_slug_like_instance_name(self) -> None:
+        config = ScorerConfig(
+            plugin="heretic.scorers.keyword_rate.KeywordRate",
+            optimization="minimize",
+            instance_name="small-1",
+        )
+
+        self.assertEqual(config.instance_name, "small-1")
+
+    def test_rejects_empty_instance_name(self) -> None:
+        with self.assertRaises(ValidationError):
+            ScorerConfig(
+                plugin="heretic.scorers.keyword_rate.KeywordRate",
+                optimization="minimize",
+                instance_name=" \t",
+            )
+
+    def test_rejects_whitespace_in_instance_name(self) -> None:
+        for instance_name in ["small name", "small\tname", "small\nname"]:
+            with self.subTest(instance_name=instance_name):
+                with self.assertRaisesRegex(
+                    ValidationError, "whitespace is not allowed"
+                ):
+                    ScorerConfig(
+                        plugin="heretic.scorers.keyword_rate.KeywordRate",
+                        optimization="minimize",
+                        instance_name=instance_name,
+                    )
+
+    def test_rejects_dot_in_instance_name(self) -> None:
+        with self.assertRaisesRegex(ValidationError, "'\\.' is not allowed"):
+            ScorerConfig(
+                plugin="heretic.scorers.keyword_rate.KeywordRate",
+                optimization="minimize",
+                instance_name="small.name",
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()