diff --git a/lib/galaxy/tool_util/parameters/__init__.py b/lib/galaxy/tool_util/parameters/__init__.py
index eafe4af34b98..ffd307f98e78 100644
--- a/lib/galaxy/tool_util/parameters/__init__.py
+++ b/lib/galaxy/tool_util/parameters/__init__.py
@@ -58,6 +58,7 @@
     flat_state_path,
     keys_starting_with,
     repeat_inputs_to_array,
+    validate_explicit_conditional_test_value,
     visit_input_values,
 )
 
@@ -100,6 +101,7 @@
     "validate_test_case",
     "validate_workflow_step",
     "validate_workflow_step_linked",
+    "validate_explicit_conditional_test_value",
     "ToolState",
     "TestCaseToolState",
     "ToolParameterT",
diff --git a/lib/galaxy/tool_util/parameters/visitor.py b/lib/galaxy/tool_util/parameters/visitor.py
index 9e411c050d54..363dd9298bc0 100644
--- a/lib/galaxy/tool_util/parameters/visitor.py
+++ b/lib/galaxy/tool_util/parameters/visitor.py
@@ -105,3 +105,9 @@ def repeat_inputs_to_array(flat_state_path: str, inputs: Dict[str, KVT]) -> List
         except ValueError:
             continue
     return params
+
+
+def validate_explicit_conditional_test_value(test_parameter_name: str, value: Any) -> Optional[Union[str, bool]]:
+    if value is not None and not isinstance(value, (str, bool)):
+        raise Exception(f"Invalid conditional test value ({value}) for parameter ({test_parameter_name})")
+    return cast(Optional[Union[str, bool]], value)