wrote first test for mdp pgc

tests/test_pgc.py

@@ -0,0 +1,56 @@
+from stormvogel import pgc
+import stormvogel.model
+import math
+
+
+def test_pgc_mdp():
+    # we build the model with pgc:
+    N = 2
+    p = 0.5
+    initial_state = pgc.State(math.floor(N / 2))
+
+    left = pgc.Action(["left"])
+    right = pgc.Action(["right"])
+
+    def available_actions(s: pgc.State):
+        return [left, right]
+
+    def delta(s: pgc.State, action: pgc.Action):
+        if action == left:
+            return (
+                [(p, pgc.State(x=s.x + 1)), (1 - p, pgc.State(x=s.x))]
+                if s.x < N
+                else []
+            )
+        elif action == right:
+            return (
+                [(p, pgc.State(x=s.x - 1)), (1 - p, pgc.State(x=s.x))]
+                if s.x > 0
+                else []
+            )
+
+    pgc_model = stormvogel.pgc.build_pgc(
+        delta=delta,
+        available_actions=available_actions,
+        initial_state_pgc=initial_state,
+    )
+
+    # we build the model in the regular way:
+    model = stormvogel.model.new_mdp(create_initial_state=False)
+    state1 = model.new_state(labels=["init", "1"], features={"x": 1})
+    state2 = model.new_state(labels=["2"], features={"x": 2})
+    state0 = model.new_state(labels=["0"], features={"0": 0})
+    left = model.new_action("left", frozenset({"left"}))
+    right = model.new_action("right", frozenset({"right"}))
+    branch11 = stormvogel.model.Branch([(0.5, state1), (0.5, state2)])
+    branch12 = stormvogel.model.Branch([(0.5, state1), (0.5, state0)])
+    branch0 = stormvogel.model.Branch([(0.5, state0), (0.5, state1)])
+    branch2 = stormvogel.model.Branch([(0.5, state2), (0.5, state1)])
+
+    model.add_transitions(
+        state1, stormvogel.model.Transition({left: branch11, right: branch12})
+    )
+    model.add_transitions(state2, stormvogel.model.Transition({right: branch2}))
+    model.add_transitions(state0, stormvogel.model.Transition({left: branch0}))
+
+    assert model == pgc_model