Updated sheerka.value() and added unit tests

tests/test_sheerka.py

@@ -3,7 +3,7 @@ import os
 from os import path
 import shutil
 
-from core.builtin_concepts import BuiltinConcepts, ReturnValueConcept
+from core.builtin_concepts import BuiltinConcepts, ReturnValueConcept, UserInputConcept
 from core.concept import Concept, PROPERTIES_TO_SERIALIZE, Property
 from core.sheerka import Sheerka, ExecutionContext
 from evaluators.MutipleSameSuccessEvaluator import MultipleSameSuccessEvaluator
@@ -320,9 +320,16 @@ def test_i_cannot_instantiate_when_properties_are_not_recognized():
 @pytest.mark.parametrize("concept, allow_non_body, expected", [
     (None, False, None),
     (3.14, False, 3.14),
+    ("foo", False, "foo"),
+    (True, False, True),
     (Concept("name", body="foo"), False, "foo"),
     (Concept("name"), True, Concept("name")),
     (ConceptWithGetValue("name").set_prop("my_prop", "my_value"), True, "my_value"),
+    (ReturnValueConcept(value="return_value"), False, "return_value"),
+    (ReturnValueConcept(value=Concept(key=BuiltinConcepts.USER_INPUT, body="text"), status=True), False, "text"),
+    (ReturnValueConcept(value=UserInputConcept("text"), status=True), False, "text"),
+    (Concept("name", body=["foo", "bar"]), False, ["foo", "bar"]),
+    (Concept("name", body=["foo"]), False, "foo"),
 ])
 def test_i_can_get_value(concept, allow_non_body, expected):
     sheerka = get_sheerka()