Added chicken and egg recursion detection

tests/core/test_sheerka.py

@@ -242,3 +242,41 @@ class TestSheerka(TestUsingFileBasedSheerka):
         # only test a random one, it will be the same for the others
         sheerka = self.get_sheerka()
         assert not sheerka.is_success(sheerka.new(BuiltinConcepts.TOO_MANY_SUCCESS))
+
+    def test_cache_is_updated_after_get(self):
+        sheerka = self.get_sheerka()
+
+        # updated when by_key returns one element
+        sheerka.create_new_concept(self.get_context(sheerka), Concept("foo", body="1"))
+        sheerka.reset_cache()
+        sheerka.get("foo")
+        assert "foo" in sheerka.cache_by_key
+        assert "1001" in sheerka.cache_by_id
+
+        # updated when by_key returns two elements
+        sheerka.create_new_concept(self.get_context(sheerka), Concept("foo", body="2"))
+        sheerka.reset_cache()
+        sheerka.get("foo")
+        assert "foo" in sheerka.cache_by_key
+        assert "1001" in sheerka.cache_by_id
+        assert "1002" in sheerka.cache_by_id
+
+        # updated when by_id
+        sheerka.reset_cache()
+        sheerka.get_by_id("1001")
+        assert "1001" in sheerka.cache_by_id
+        assert "foo" not in sheerka.cache_by_key  # cache_by_key not updated as "1001" is not the only one
+
+    def test_i_can_get_by_key_several_times(self):
+        sheerka = self.get_sheerka()
+        sheerka.create_new_concept(self.get_context(sheerka), Concept("foo", body="1"))
+        sheerka.create_new_concept(self.get_context(sheerka), Concept("foo", body="2"))
+
+        sheerka.reset_cache()
+        sheerka.get("foo", "1001")  # only one element requested. But the cache must be updated with two elements
+
+        # let's check it
+        concepts = sheerka.get("foo")
+        assert len(concepts) == 2
+        assert concepts[0].id == "1001"
+        assert concepts[1].id == "1002"