#902 - replaced 'final_node_<placeholder>' with 'reference_node_<placeholder>' in methods for scoring of os_state, file_system_state, service state and operating state. This fixed the reward function so it is checked at each step for node operating system state, operating state, file system state and service state.

- Added unit tests.

tests/test_reward.py

@@ -0,0 +1,31 @@
+from tests import TEST_CONFIG_ROOT
+from tests.conftest import _get_primaite_env_from_config
+
+
+def test_rewards_are_being_penalised_at_each_step_function():
+    """
+    Test that hardware state is penalised at each step.
+
+    When the initial state is OFF compared to reference state which is ON.
+    """
+    env = _get_primaite_env_from_config(
+        main_config_path=TEST_CONFIG_ROOT / "one_node_states_on_off_main_config.yaml",
+        lay_down_config_path=TEST_CONFIG_ROOT
+        / "one_node_states_on_off_lay_down_config.yaml",
+    )
+
+    """
+    On different steps (of the 13 in total) these are the following rewards for config_6 which are activated:
+        File System State: goodShouldBeCorrupt = 5 (Step 3)
+        Hardware State: onShouldBeOff = -2 (Step 5)
+        Service State: goodShouldBeCompromised = 5 (Step 7)
+        Operating System State (Software State): goodShouldBeCompromised = 5 (Step 10)
+
+    Total Reward: -2 - 2 + 5 + 5 + 5 + 5 + 5 + 5 = 26
+    Step Count: 13
+
+    For the 4 steps where this occurs the average reward is:
+        Average Reward: 2 (26 / 13)
+    """
+    print("average reward", env.average_reward)
+    assert env.average_reward == 2.0