def test_expand():
root = BanditNode()
state = FakeGameState()
root.expand(state)
children = root.child_nodes()
assert len(children) == 2
assert children[0].action == 0
assert children[1].action == 1
assert children[0].parent == root
assert children[1].parent == root
def test_backup_with_value():
root = BanditNode()
state = FakeGameState()
root.expand(state)
children = root.child_nodes()
state.play(children[0].action)
children[0].expand(state)
children[0].child_nodes()[0].backup(1)
assert children[0].value() == -1
assert children[1].value() == 0
assert children[0].child_nodes()[0].value() == 1
assert children[0].child_nodes()[1].value() == 0
children[0].child_nodes()[1].backup(-1)
assert children[0].value() == 0
assert children[0].child_nodes()[0].value() == 1
assert children[0].child_nodes()[1].value() == -1
def test_is_root():
root = BanditNode()
state = FakeGameState()
root.expand(state)
assert root.is_root()
for child in root.child_nodes():
assert not child.is_root()
def test_ucb_initial_explore():
root = BanditNode()
state = FakeGameState()
root.expand(state)
children = root.child_nodes()
for child in children:
assert BanditNode.ucb_value(child, 1) == float('inf')
def test_num_nodes():
root = BanditNode()
state = FakeGameState()
root.expand(state)
assert root.num_nodes() == 3
for child in root.child_nodes():
assert child.num_nodes() == 1
def test_child_nodes():
root = BanditNode()
state = FakeGameState()
root.expand(state)
assert len(root.child_nodes()) == 2
for child in root.child_nodes():
assert len(child.child_nodes()) == 0
def test_backup_with_ucb():
root = BanditNode()
state = FakeGameState()
root.expand(state)
children = root.child_nodes()
state.play(children[0].action)
children[0].expand(state)
children[0].child_nodes()[0].backup(-1)
children[0].child_nodes()[1].backup(1)
assert BanditNode.ucb_value(children[0], 1) == 0.8325546111576977
assert BanditNode.ucb_value(children[0].child_nodes()[0], 1) == (
0.17741002251547466)
assert BanditNode.ucb_value(children[0].child_nodes()[1], 1) == (
2.177410022515475)
def test_info_strings_to_json():
root = BanditNode()
state = FakeGameState()
root.expand(state)
children = root.child_nodes()
children[0].backup(1)
children[1].backup(-1)
info = root.info_strings_to_dict()
assert info["info"] == "avg_reward: 0.0 num_visits: 2"
assert info["children"][0][
"info"] == "player: 0 action: 0 | avg_reward: 1.0 num_visits: 1"
assert info["children"][1][
"info"] == "player: 0 action: 1 | avg_reward: -1.0 num_visits: 1"
def test_is_leaf():
root = BanditNode()
assert root.is_leaf()
state = FakeGameState()
root.expand(state)
assert not root.is_leaf()
def test_child_nodes():
root = BanditNode()
assert root.child_nodes() == []
def test_str():
root = BanditNode()
state = FakeGameState()
assert str(root) == '{\n "info": "avg_reward: 0 num_visits: 0"\n}'