add inital test suite, fix minor Mapping group bug

tests/test_schema.py

@@ -0,0 +1,26 @@
+from co3.components import Relation
+
+from setups import vegetables as veg
+
+
+def test_schema_get():
+    veg_comp_raw = veg.vegetable_schema._component_map.get('vegetable')
+    veg_comp     = veg.vegetable_schema.get_component('vegetable')
+
+    assert veg_comp_raw is veg_comp
+
+def test_schema_contains():
+    vegetable_comp    = veg.vegetable_schema.get_component('vegetable')
+    tomato_comp       = veg.vegetable_schema.get_component('tomato')
+    tomato_aging_comp = veg.vegetable_schema.get_component('tomato_aging_states')
+
+    assert vegetable_comp in veg.vegetable_schema
+    assert tomato_comp in veg.vegetable_schema
+    assert tomato_aging_comp in veg.vegetable_schema
+
+def test_schema_add():
+    veg.vegetable_schema.add_component(Relation[int]('a', 1))
+    veg.vegetable_schema.add_component(Relation[int]('b', 2))
+
+    assert veg.vegetable_schema.get_component('a') is not None
+    assert veg.vegetable_schema.get_component('b') is not None