Raise error when specifying transformation without bounds (#451)

This PR fixes #449 by now checking whether a `NumericalTarget` has
bounds if a transformation is provided.

Introduces a new step in the validation, raising a value error if the
user provides a transformation but no bounds. Also adds an according
test.

CHANGELOG.md

@@ -31,6 +31,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Search spaces are now stateless, preventing unintended side effects that could lead to
   incorrect candidate sets when reused in different optimization contexts
 - `qNIPV` not working with single `MIN` targets
+- Passing a `TargetTransformation` without passing `bounds` when createing a 
+  `NumericalTarget` now raises an error
 
 ### Deprecations
 - Passing a dataframe via the `data` argument to `Objective.transform` is no longer

baybe/targets/numerical.py

@@ -113,11 +113,18 @@ def _validate_bounds(self, _: Any, bounds: Interval) -> None:  # noqa: DOC101, D
     def _validate_transformation(  # noqa: DOC101, DOC103
         self, _: Any, value: TargetTransformation | None
     ) -> None:
-        """Validate that the given transformation is compatible with the specified mode.
+        """Validate compatability between transformation, bounds and the mode.
 
         Raises:
+            ValueError: If a target transformation was provided for an unbounded
+                target.
             ValueError: If the target transformation and mode are not compatible.
         """
+        if (value is not None) and (not self.bounds.is_bounded):
+            raise ValueError(
+                f"You specified a transformation for target '{self.name}', but "
+                f"did not specify any bounds."
+            )
         if (value is not None) and (value not in _VALID_TRANSFORMATIONS[self.mode]):
             raise ValueError(
                 f"You specified bounds for target '{self.name}', but your "

tests/hypothesis_strategies/targets.py

@@ -28,12 +28,14 @@ def numerical_targets(
     """
     name = draw(target_name)
     mode = draw(st.sampled_from(TargetMode))
+    transformation = draw(st.sampled_from(_VALID_TRANSFORMATIONS[mode]))
     if bounds_strategy is None:
         bounds_strategy = st_intervals(
-            exclude_half_bounded=True, exclude_fully_unbounded=mode is TargetMode.MATCH
+            exclude_half_bounded=True,
+            exclude_fully_unbounded=mode is TargetMode.MATCH
+            or transformation is not None,
         )
     bounds = draw(bounds_strategy)
-    transformation = draw(st.sampled_from(_VALID_TRANSFORMATIONS[mode]))
 
     return NumericalTarget(
         name=name, mode=mode, bounds=bounds, transformation=transformation

tests/validation/test_target_validation.py

@@ -53,3 +53,15 @@ def test_binary_target_invalid_values(choices, error, match):
             success_value=choices[0],
             failure_value=choices[1],
         )
+
+
+@pytest.mark.parametrize(
+    "mode",
+    ["MIN", "MAX"],
+)
+def test_providing_transformation_without_bounds(mode):
+    """Providing a transformation without bounds raises an error."""
+    with pytest.raises(ValueError, match="but did not specify any bounds."):
+        NumericalTarget(
+            name="transformation_without_bounds", mode=mode, transformation="LINEAR"
+        )