Implemented ConceptManager with concept creation, modification and deletion

tests/core/test_SheerkaEvaluateConcept.py

@@ -375,6 +375,26 @@ class TestSheerkaEvaluateConcept(TestUsingMemoryBasedSheerka):
         assert evaluated.get_metadata().is_evaluated
         assert sheerka.objvalue(evaluated) == 2
 
+    def test_i_can_evaluate_a_concept_that_references_another_concept_twice(self):
+        """
+        Test that a new instance of concept is return when the metadata refers to a concept
+        :return:
+        """
+        sheerka, context, predicate, foo = self.init_concepts(
+            Concept("Sometimes True", body="in_context('a')"),
+            Concept("foo", pre="c:Sometimes True:"))
+
+        foo1 = sheerka.new("foo")
+        foo1 = sheerka.evaluate_concept(context, foo1)  # 'a' is not in context, so it fails
+
+        context2 = self.get_context(sheerka)
+        context2.add_to_protected_hints('a')
+        foo2 = sheerka.new("foo")
+        foo2 = sheerka.evaluate_concept(context2, foo2)  # 'a' in context + new instance of 'Sometimes True'
+
+        assert sheerka.isinstance(foo1, BuiltinConcepts.CONDITION_FAILED)
+        assert sheerka.isinstance(foo2, "foo")
+
     def test_i_can_reference_sheerka(self):
         sheerka = self.get_sheerka()
 
@@ -624,8 +644,8 @@ class TestSheerkaEvaluateConcept(TestUsingMemoryBasedSheerka):
             eval_body=True
         )
 
-        sheerka.add_in_cache(one_str)
-        sheerka.add_in_cache(one_digit)
+        sheerka.test_only_add_in_cache(one_str)
+        sheerka.test_only_add_in_cache(one_digit)
 
         evaluated = sheerka.evaluate_concept(context, one_digit)
         assert evaluated.key == one_digit.key