Fix issue #84: value is mandatory even for no input operators

business_rules/engine.py

@@ -50,7 +50,7 @@ def check_condition(condition, defined_variables):
     variables, values, and the comparison operator. The defined_variables
     object must have a variable defined for any variables in this condition.
     """
-    name, op, value = condition['name'], condition['operator'], condition['value']
+    name, op, value = condition['name'], condition['operator'], condition.get('value', ValueError)
     operator_type = _get_variable_value(defined_variables, name)
     return _do_operator_comparison(operator_type, op, value)
 
@@ -82,6 +82,8 @@ def fallback(*args, **kwargs):
     method = getattr(operator_type, operator_name, fallback)
     if getattr(method, 'input_type', '') == FIELD_NO_INPUT:
         return method()
+    if comparison_value == ValueError:
+        raise AssertionError("Operator '{0}' needs a value property".format(operator_name))
     return method(comparison_value)
 
 

tests/test_integration.py

@@ -1,3 +1,5 @@
+import pytest
+
 from business_rules.engine import check_condition
 from business_rules import export_rule_data
 from business_rules.actions import rule_action, BaseActions
@@ -45,7 +47,6 @@ def test_true_boolean_variable(self):
         condition = {
             'name': 'true_bool',
             'operator': 'is_true',
-            'value': ''
         }
         res = check_condition(condition, SomeVariables())
         self.assertTrue(res)
@@ -54,11 +55,19 @@ def test_false_boolean_variable(self):
         condition = {
             'name': 'true_bool',
             'operator': 'is_false',
-            'value': ''
         }
         res = check_condition(condition, SomeVariables())
         self.assertFalse(res)
 
+    def test_check_when_incomplete_rule(self):
+        condition = {'name': 'foo',
+                     'operator': 'contains'}
+        with pytest.raises(AssertionError) as exc_info:
+            self.assertTrue(check_condition(condition, SomeVariables()))
+
+        assert str(exc_info.value) == "Operator 'contains' needs a value property"
+
+
     def test_check_true_condition_happy_path(self):
         condition = {'name': 'foo',
                      'operator': 'contains',