Merge branch 'master' into develop-sac-apex

Project/Assets/ML-Agents/Examples/3DBall/Scripts/Ball3DAgent.cs

         SetResetParameters();
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[2];
-
-        action[0] = -Input.GetAxis("Horizontal");
-        action[1] = Input.GetAxis("Vertical");
-        return action;
+        actionsOut[0] = -Input.GetAxis("Horizontal");
+        actionsOut[1] = Input.GetAxis("Vertical");
     }
 
     public void SetBall()

Project/Assets/ML-Agents/Examples/Bouncer/Scripts/BouncerAgent.cs

         }
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[3];
-
-        action[0] = Input.GetAxis("Horizontal");
-        action[1] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
-        action[2] = Input.GetAxis("Vertical");
-        return action;
+        actionsOut[0] = Input.GetAxis("Horizontal");
+        actionsOut[1] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
+        actionsOut[2] = Input.GetAxis("Vertical");
     }
 
     void Update()

Project/Assets/ML-Agents/Examples/FoodCollector/Scripts/FoodCollectorAgent.cs

         MoveAgent(vectorAction);
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[4];
-            action[2] = 2f;
+            actionsOut[2] = 2f;
-            action[0] = 1f;
+            actionsOut[0] = 1f;
-            action[2] = 1f;
+            actionsOut[2] = 1f;
-            action[0] = 2f;
+            actionsOut[0] = 2f;
-        action[3] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
-        return action;
+        actionsOut[3] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
     }
 
     public override void OnEpisodeBegin()

Project/Assets/ML-Agents/Examples/GridWorld/Scripts/GridAgent.cs

         }
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
+        actionsOut[0] = k_NoAction;
-            return new float[] { k_Right };
+            actionsOut[0] = k_Right;
-            return new float[] { k_Up };
+            actionsOut[0] = k_Up;
-            return new float[] { k_Left };
+            actionsOut[0] = k_Left;
-            return new float[] { k_Down };
+            actionsOut[0] = k_Down;
-        return new float[] { k_NoAction };
     }
 
     // to be implemented by the developer

Project/Assets/ML-Agents/Examples/Hallway/Scripts/HallwayAgent.cs

         }
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
+        actionsOut[0] = 0;
-            return new float[] { 3 };
+            actionsOut[0] = 3;
-        if (Input.GetKey(KeyCode.W))
+        else if (Input.GetKey(KeyCode.W))
-            return new float[] { 1 };
+            actionsOut[0] = 1;
-        if (Input.GetKey(KeyCode.A))
+        else if (Input.GetKey(KeyCode.A))
-            return new float[] { 4 };
+            actionsOut[0] = 4;
-        if (Input.GetKey(KeyCode.S))
+        else if (Input.GetKey(KeyCode.S))
-            return new float[] { 2 };
+            actionsOut[0] = 2;
-        return new float[] { 0 };
     }
 
     public override void OnEpisodeBegin()

Project/Assets/ML-Agents/Examples/PushBlock/Scripts/PushAgentBasic.cs

         AddReward(-1f / maxStep);
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
+        actionsOut[0] = 0;
-            return new float[] { 3 };
+            actionsOut[0] = 3;
-        if (Input.GetKey(KeyCode.W))
+        else if (Input.GetKey(KeyCode.W))
-            return new float[] { 1 };
+            actionsOut[0] = 1;
-        if (Input.GetKey(KeyCode.A))
+        else if (Input.GetKey(KeyCode.A))
-            return new float[] { 4 };
+            actionsOut[0] = 4;
-        if (Input.GetKey(KeyCode.S))
+        else if (Input.GetKey(KeyCode.S))
-            return new float[] { 2 };
+            actionsOut[0] = 2;
-        return new float[] { 0 };
     }
 
     /// <summary>

Project/Assets/ML-Agents/Examples/Pyramids/Scripts/PyramidAgent.cs

         MoveAgent(vectorAction);
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
+        actionsOut[0] = 0;
-            return new float[] { 3 };
+            actionsOut[0] = 3;
-        if (Input.GetKey(KeyCode.W))
+        else if (Input.GetKey(KeyCode.W))
-            return new float[] { 1 };
+            actionsOut[0] = 1;
-        if (Input.GetKey(KeyCode.A))
+        else if (Input.GetKey(KeyCode.A))
-            return new float[] { 4 };
+            actionsOut[0] = 4;
-        if (Input.GetKey(KeyCode.S))
+        else if (Input.GetKey(KeyCode.S))
-            return new float[] { 2 };
+            actionsOut[0] = 2;
-        return new float[] { 0 };
     }
 
     public override void OnEpisodeBegin()

Project/Assets/ML-Agents/Examples/Soccer/Scripts/AgentSoccer.cs

         MoveAgent(vectorAction);
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[3];
-            action[0] = 1f;
+            actionsOut[0] = 1f;
-            action[0] = 2f;
+            actionsOut[0] = 2f;
-            action[2] = 1f;
+            actionsOut[2] = 1f;
-            action[2] = 2f;
+            actionsOut[2] = 2f;
-            action[1] = 1f;
+            actionsOut[1] = 1f;
-            action[1] = 2f;
+            actionsOut[1] = 2f;
-        return action;
     }
     /// <summary>
     /// Used to provide a "kick" to the ball.

Project/Assets/ML-Agents/Examples/Tennis/Scripts/TennisAgent.cs

         m_TextComponent.text = score.ToString();
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[3];
-
-        action[0] = Input.GetAxis("Horizontal");    // Racket Movement
-        action[1] = Input.GetKey(KeyCode.Space) ? 1f : 0f;   // Racket Jumping
-        action[2] = Input.GetAxis("Vertical");   // Racket Rotation  
-        return action;
+        actionsOut[0] = Input.GetAxis("Horizontal");    // Racket Movement
+        actionsOut[1] = Input.GetKey(KeyCode.Space) ? 1f : 0f;   // Racket Jumping
+        actionsOut[2] = Input.GetAxis("Vertical");   // Racket Rotation
     }
 
     public override void OnEpisodeBegin()

Project/Assets/ML-Agents/Examples/WallJump/Scripts/WallJumpAgent.cs

         }
     }
 
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[4];
-            action[1] = 2f;
+            actionsOut[1] = 2f;
-            action[0] = 1f;
+            actionsOut[0] = 1f;
-            action[1] = 1f;
+            actionsOut[1] = 1f;
-            action[0] = 2f;
+            actionsOut[0] = 2f;
-        action[3] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
-        return action;
+        actionsOut[3] = Input.GetKey(KeyCode.Space) ? 1.0f : 0.0f;
     }
 
     // Detect when the agent hits the goal

com.unity.ml-agents/CHANGELOG.md

  - Added ability to start training (initialize model weights) from a previous run ID. (#3710)
  - The internal event `Academy.AgentSetStatus` was renamed to `Academy.AgentPreStep` and made public.
  - The offset logic was removed from DecisionRequester.
+ - The signature of `Agent.Heuristic()` was changed to take a `float[]` as a parameter, instead of returning the array. This was done to prevent a common source of error where users would return arrays of the wrong size.
+ - The communication API version has been bumped up to 1.0.0 and will use [Semantic Versioning](https://semver.org/) to do compatibility checks for communication between Unity and the Python process.
+ - The obsolete `Agent` methods `GiveModel`, `Done`, `InitializeAgent`, `AgentAction` and `AgentReset` have been removed.
 
 ### Minor Changes
  - Format of console output has changed slightly and now matches the name of the model/summary directory. (#3630, #3616)
  - Fixed an issue where exceptions from environments provided a returncode of 0. (#3680)
  - Running `mlagents-learn` with the same `--run-id` twice will no longer overwrite the existing files. (#3705)
  - `StackingSensor` was changed from `internal` visibility to `public`
+ - Updated Barracuda to 0.6.3-preview.
  - Model updates now happen asynchronously with environment steps. (#3690)
  - `num_updates` and `train_interval` for SAC were replaced with `steps_per_update`. (#3690)
 

com.unity.ml-agents/Runtime/Agent.cs

             m_RequestDecision = false;
         }
 
-        [Obsolete("GiveModel() has been deprecated, use SetModel() instead.")]
-        public void GiveModel(
-            string behaviorName,
-            NNModel model,
-            InferenceDevice inferenceDevice = InferenceDevice.CPU)
-        {
-            SetModel(behaviorName, model, inferenceDevice);
-        }
-
         /// <summary>
         /// Updates the Model for the agent. Any model currently assigned to the
         /// agent will be replaced with the provided one. If the arguments are
             TimerStack.Instance.SetGauge(gaugeName, GetCumulativeReward());
         }
 
-        [Obsolete("Done() has been deprecated, use EndEpisode() instead.")]
-        public void Done()
-        {
-            EndEpisode();
-        }
-
         /// <summary>
         /// Sets the done flag to true.
         /// </summary>
             }
         }
 
-        [Obsolete("InitializeAgent() has been deprecated, use Initialize() instead.")]
-        public virtual void InitializeAgent()
-        {
-        }
-
         /// <summary>
         /// Initializes the agent, called once when the agent is enabled. Can be
         /// left empty if there is no special, unique set-up behavior for the
         /// One sample use is to store local references to other objects in the
         /// scene which would facilitate computing this agents observation.
         /// </remarks>
-        public virtual void Initialize()
-        {
-#pragma warning disable 0618
-            InitializeAgent();
-#pragma warning restore 0618
-        }
+        public virtual void Initialize(){}
 
         /// <summary>
         /// When the Agent uses Heuristics, it will call this method every time it
         /// <returns> A float array corresponding to the next action of the Agent
         /// </returns>
-        public virtual float[] Heuristic()
+        public virtual void Heuristic(float[] actionsOut)
-            var param = m_PolicyFactory.brainParameters;
-
-            return new float[param.numActions];
+            Array.Clear(actionsOut, 0, actionsOut.Length);
         }
 
         /// <summary>
         {
         }
 
-        [Obsolete("AgentAction() has been deprecated, use OnActionReceived() instead.")]
-        public virtual void AgentAction(float[] vectorAction)
-        {
-        }
-
         /// <summary>
         /// Specifies the agent behavior at every step based on the provided
         /// action.
         /// will be of length 1.
         /// </param>
-        public virtual void OnActionReceived(float[] vectorAction)
-        {
-#pragma warning disable 0618
-            AgentAction(m_Action.vectorActions);
-#pragma warning restore 0618
-        }
-
-        [Obsolete("AgentReset() has been deprecated, use OnEpisodeBegin() instead.")]
-        public virtual void AgentReset()
-        {
-        }
+        public virtual void OnActionReceived(float[] vectorAction){}
 
         /// <summary>
         /// Specifies the agent behavior when being reset, which can be due to
-        public virtual void OnEpisodeBegin()
-        {
-#pragma warning disable 0618
-            AgentReset();
-#pragma warning restore 0618
-        }
+        public virtual void OnEpisodeBegin(){}
 
         /// <summary>
         /// Returns the last action that was decided on by the Agent

com.unity.ml-agents/Runtime/Communicator/RpcCommunicator.cs

 
         #region Initialization
 
+        internal static bool CheckCommunicationVersionsAreCompatible(
+            string unityCommunicationVersion,
+            string pythonApiVersion,
+            string pythonLibraryVersion)
+        {
+            var unityVersion = new Version(unityCommunicationVersion);
+            var pythonVersion = new Version(pythonApiVersion);
+            if (unityVersion.Major == 0)
+            {
+                if (unityVersion.Major != pythonVersion.Major || unityVersion.Minor != pythonVersion.Minor)
+                {
+                    return false;
+                }
+
+            }
+            else if (unityVersion.Major != pythonVersion.Major)
+            {
+                return false;
+            }
+            else if (unityVersion.Minor != pythonVersion.Minor)
+            {
+                // Even if we initialize, we still want to check to make sure that we inform users of minor version
+                // changes.  This will surface any features that may not work due to minor version incompatibilities.
+                Debug.LogWarningFormat(
+                    "WARNING: The communication API versions between Unity and python differ at the minor version level. " +
+                    "Python API: {0}, Unity API: {1} Python Library Version: {2} .\n" +
+                    "This means that some features may not work unless you upgrade the package with the lower version." +
+                    "Please find the versions that work best together from our release page.\n" +
+                    "https://github.com/Unity-Technologies/ml-agents/releases",
+                    pythonApiVersion, unityCommunicationVersion, pythonLibraryVersion
+                );
+            }
+            return true;
+        }
+
         /// <summary>
         /// Sends the initialization parameters through the Communicator.
         /// Is used by the academy to send initialization parameters to the communicator.
                     },
                     out input);
 
+                var pythonCommunicationVersion = initializationInput.RlInitializationInput.CommunicationVersion;
+                var pythonPackageVersion = initializationInput.RlInitializationInput.PackageVersion;
+                var unityCommunicationVersion = initParameters.unityCommunicationVersion;
+
+                var communicationIsCompatible = CheckCommunicationVersionsAreCompatible(unityCommunicationVersion,
+                    pythonCommunicationVersion,
+                    pythonPackageVersion);
+
-                    var pythonCommunicationVersion = initializationInput.RlInitializationInput.CommunicationVersion;
-                    var pythonPackageVersion = initializationInput.RlInitializationInput.PackageVersion;
-                    if (pythonCommunicationVersion != initParameters.unityCommunicationVersion)
+                    if (!communicationIsCompatible)
-                            "Communication protocol between python ({0}) and Unity ({1}) don't match. " +
-                            "Python library version: {2}.",
+                            "Communication protocol between python ({0}) and Unity ({1}) have different " +
+                            "versions which make them incompatible. Python library version: {2}.",
                             pythonCommunicationVersion, initParameters.unityCommunicationVersion,
                             pythonPackageVersion
                         );

com.unity.ml-agents/Runtime/Policies/BehaviorParameters.cs

             get { return m_BehaviorName + "?team=" + TeamId; }
         }
 
-        internal IPolicy GeneratePolicy(Func<float[]> heuristic)
+        internal IPolicy GeneratePolicy(HeuristicPolicy.ActionGenerator heuristic)
-                    return new HeuristicPolicy(heuristic);
+                    return new HeuristicPolicy(heuristic, m_BrainParameters.numActions);
                 case BehaviorType.InferenceOnly:
                 {
                     if (m_Model == null)
                     }
                     else
                     {
-                        return new HeuristicPolicy(heuristic);
+                        return new HeuristicPolicy(heuristic, m_BrainParameters.numActions);
-                    return new HeuristicPolicy(heuristic);
+                    return new HeuristicPolicy(heuristic, m_BrainParameters.numActions);
             }
         }
 

com.unity.ml-agents/Runtime/Policies/HeuristicPolicy.cs

     /// </summary>
     internal class HeuristicPolicy : IPolicy
     {
-        Func<float[]> m_Heuristic;
+        public delegate void ActionGenerator(float[] actionsOut);
+        ActionGenerator m_Heuristic;
+        int m_numActions;
 
         WriteAdapter m_WriteAdapter = new WriteAdapter();
         NullList m_NullList = new NullList();
-        public HeuristicPolicy(Func<float[]> heuristic)
+        public HeuristicPolicy(ActionGenerator heuristic, int numActions)
+            m_numActions = numActions;
         }
 
         /// <inheritdoc />
             if (!info.done)
             {
-                m_LastDecision = m_Heuristic.Invoke();
+                // Reset m_LastDecision each time.
+                 m_LastDecision = new float[m_numActions];
+                 m_Heuristic.Invoke(m_LastDecision);
             }
         }
 

com.unity.ml-agents/Tests/Editor/BehaviorParameterTests.cs

     [TestFixture]
     public class BehaviorParameterTests
     {
-        static float[] DummyHeuristic()
+        static void DummyHeuristic(float[] actionsOut)
-            return null;
+            // No-op
         }
 
         [Test]

com.unity.ml-agents/Tests/Editor/MLAgentsEditModeTest.cs

             agentActionCallsForEpisode = 0;
         }
 
-        public override float[] Heuristic()
+        public override void Heuristic(float[] actionsOut)
-            return new float[0];
         }
     }
 

com.unity.ml-agents/Tests/Runtime/RuntimeAPITest.cs

     {
         public int numHeuristicCalls;
 
-        public override float[] Heuristic()
+        public override void Heuristic(float[] actionsOut)
-            return base.Heuristic();
+            base.Heuristic(actionsOut);
-    }// Simple SensorComponent that sets up a StackingSensor
+    }
+
+    // Simple SensorComponent that sets up a StackingSensor
     public class StackingComponent : SensorComponent
     {
         public SensorComponent wrappedComponent;

com.unity.ml-agents/package.json

   "unity": "2018.4",
   "description": "Add interactivity to your game with Machine Learning Agents trained using Deep Reinforcement Learning.",
   "dependencies": {
-    "com.unity.barracuda": "0.6.1-preview"
+    "com.unity.barracuda": "0.6.3-preview"
   }
 }

docs/Getting-Started.md

   step.
 * `Agent.Heuristic()` - When the `Behavior Type` is set to `Heuristic Only` in the Behavior
   Parameters of the Agent, the Agent will use the `Heuristic()` method to generate
-  the actions of the Agent. As such, the `Heuristic()` method returns an array of
+  the actions of the Agent. As such, the `Heuristic()` method takes an array of
   floats. In the case of the Ball 3D Agent, the `Heuristic()` method converts the
   keyboard inputs into actions.
 

docs/Learning-Environment-Create-New.md

 The `Heuristic()` method will look like this :
 
 ```csharp
-    public override float[] Heuristic()
+    public override void Heuristic(float[] actionsOut)
-        var action = new float[2];
-        action[0] = Input.GetAxis("Horizontal");
-        action[1] = Input.GetAxis("Vertical");
-        return action;
+        actionsOut[0] = Input.GetAxis("Horizontal");
+        actionsOut[1] = Input.GetAxis("Vertical");
     }
 ```
 

docs/Learning-Environment-Design-Agents.md

 
 Note that when you are programming actions for an agent, it is often helpful to
 test your action logic using the `Heuristic()` method of the Agent,
-which lets you map keyboard
-commands to actions.
+which lets you map keyboard commands to actions.
 
 The [3DBall](Learning-Environment-Examples.md#3dball-3d-balance-ball) and
 [Area](Learning-Environment-Examples.md#push-block) example environments are set

docs/Migrating.md

 * Running with the same `--run-id` twice will now throw an error.
 * Removed the multi-agent gym option from the gym wrapper. For multi-agent scenarios, use the [Low Level Python API](Python-API.md).
 * The low level Python API has changed. You can look at the document [Low Level Python API documentation](Python-API.md) for more information. If you use `mlagents-learn` for training, this should be a transparent change.
-* The `play_against_current_self_ratio` self-play trainer hyperparameter has been renamed to `play_against_latest_model_ratio`
-* The Jupyter notebooks have been removed from the repository.
-* `Academy.FloatProperties` was removed.
-* `Academy.RegisterSideChannel` and `Academy.UnregisterSideChannel` were removed.
+* The obsolete `Agent` methods `GiveModel`, `Done`, `InitializeAgent`, `AgentAction` and `AgentReset` have been removed.
+* The signature of `Agent.Heuristic()` was changed to take a `float[]` as a parameter, instead of returning the array. This was done to prevent a common source of error where users would return arrays of the wrong size.
-
+* The Jupyter notebooks have been removed from the repository.
+* `Academy.FloatProperties` was removed.
+* `Academy.RegisterSideChannel` and `Academy.UnregisterSideChannel` were removed.
+* If your Agent class overrides `Heuristic()`, change the signature to `public override void Heuristic(float[] actionsOut)` and assign values to `actionsOut` instead of returning an array.
-
 
 ## Migrating from 0.14 to 0.15
 

ml-agents-envs/mlagents_envs/environment.py

 import atexit
+from distutils.version import StrictVersion
 import glob
 import uuid
 import numpy as np
 import signal
 import struct
 
-
 logger = get_logger(__name__)
 
 
     # Command line argument used to pass the port to the executable environment.
     PORT_COMMAND_LINE_ARG = "--mlagents-port"
 
+    @staticmethod
+    def _raise_version_exception(unity_com_ver: str) -> None:
+        raise UnityEnvironmentException(
+            f"The communication API version is not compatible between Unity and python. "
+            f"Python API: {UnityEnvironment.API_VERSION}, Unity API: {unity_com_ver}.\n "
+            f"Please go to https://github.com/Unity-Technologies/ml-agents/releases/tag/latest_release "
+            f"to download the latest version of ML-Agents."
+        )
+
+    @staticmethod
+    def check_communication_compatibility(
+        unity_com_ver: str, python_api_version: str, unity_package_version: str
+    ) -> bool:
+        unity_communicator_version = StrictVersion(unity_com_ver)
+        api_version = StrictVersion(python_api_version)
+        if unity_communicator_version.version[0] == 0:
+            if (
+                unity_communicator_version.version[0] != api_version.version[0]
+                or unity_communicator_version.version[1] != api_version.version[1]
+            ):
+                # Minor beta versions differ.
+                return False
+        elif unity_communicator_version.version[0] != api_version.version[0]:
+            # Major versions mismatch.
+            return False
+        elif unity_communicator_version.version[1] != api_version.version[1]:
+            # Non-beta minor versions mismatch.  Log a warning but allow execution to continue.
+            logger.warning(
+                f"WARNING: The communication API versions between Unity and python differ at the minor version level. "
+                f"Python API: {python_api_version}, Unity API: {unity_communicator_version}.\n"
+                f"This means that some features may not work unless you upgrade the package with the lower version."
+                f"Please find the versions that work best together from our release page.\n"
+                "https://github.com/Unity-Technologies/ml-agents/releases"
+            )
+        else:
+            logger.info(
+                f"Connected to Unity environment with package version {unity_package_version} "
+                f"and communication version {unity_com_ver}"
+            )
+        return True
+
     def __init__(
         self,
         file_name: Optional[str] = None,
             self._close(0)
             raise
 
-        unity_communicator_version = aca_params.communication_version
-        if unity_communicator_version != UnityEnvironment.API_VERSION:
+        if not UnityEnvironment.check_communication_compatibility(
+            aca_params.communication_version,
+            UnityEnvironment.API_VERSION,
+            aca_params.package_version,
+        ):
-            raise UnityEnvironmentException(
-                f"The communication API version is not compatible between Unity and python. "
-                f"Python API: {UnityEnvironment.API_VERSION}, Unity API: {unity_communicator_version}.\n "
-                f"Please go to https://github.com/Unity-Technologies/ml-agents/releases/tag/latest_release "
-                f"to download the latest version of ML-Agents."
-            )
-        else:
-            logger.info(
-                f"Connected to Unity environment with package version {aca_params.package_version} "
-                f"and communication version {aca_params.communication_version}"
-            )
+            UnityEnvironment._raise_version_exception(aca_params.communication_version)
+
         self._env_state: Dict[str, Tuple[DecisionSteps, TerminalSteps]] = {}
         self._env_specs: Dict[str, BehaviorSpec] = {}
         self._env_actions: Dict[str, np.ndarray] = {}

ml-agents-envs/mlagents_envs/tests/test_envs.py

     assert comm.has_been_closed
 
 
+def test_check_communication_compatibility():
+    unity_ver = "1.0.0"
+    python_ver = "1.0.0"
+    unity_package_version = "0.15.0"
+    assert UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+    unity_ver = "1.1.0"
+    assert UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+    unity_ver = "2.0.0"
+    assert not UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+
+    unity_ver = "0.16.0"
+    python_ver = "0.16.0"
+    assert UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+    unity_ver = "0.17.0"
+    assert not UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+    unity_ver = "1.16.0"
+    assert not UnityEnvironment.check_communication_compatibility(
+        unity_ver, python_ver, unity_package_version
+    )
+
+
 def test_returncode_to_signal_name():
     assert UnityEnvironment.returncode_to_signal_name(-2) == "SIGINT"
     assert UnityEnvironment.returncode_to_signal_name(42) is None

com.unity.ml-agents/Tests/Editor/Communicator.meta

+fileFormatVersion: 2
+guid: da8f640243c749388a0329393c8fce64
+timeCreated: 1586386315

com.unity.ml-agents/Tests/Editor/Communicator/RpcCommunicatorTests.cs

+using System;
+using System.Collections;
+using System.Text.RegularExpressions;
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+
+namespace MLAgents.Tests.Communicator
+{
+    [TestFixture]
+    public class RpcCommunicatorTests
+    {
+
+        [Test]
+        public void TestCheckCommunicationVersionsAreCompatible()
+        {
+            var unityVerStr = "1.0.0";
+            var pythonVerStr = "1.0.0";
+            var pythonPackageVerStr = "0.16.0";
+
+            Assert.IsTrue(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+            LogAssert.NoUnexpectedReceived();
+
+            pythonVerStr = "1.1.0";
+            Assert.IsTrue(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+
+            // Ensure that a warning was printed.
+            LogAssert.Expect(LogType.Warning, new Regex("(.\\s)+"));
+
+            unityVerStr = "2.0.0";
+            Assert.IsFalse(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+
+            unityVerStr = "0.15.0";
+            pythonVerStr = "0.15.0";
+            Assert.IsTrue(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+            unityVerStr = "0.16.0";
+            Assert.IsFalse(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+            unityVerStr = "1.15.0";
+            Assert.IsFalse(RpcCommunicator.CheckCommunicationVersionsAreCompatible(unityVerStr,
+                pythonVerStr,
+                pythonPackageVerStr));
+
+        }
+    }
+}

com.unity.ml-agents/Tests/Editor/Communicator/RpcCommunicatorTests.cs.meta

+fileFormatVersion: 2
+guid: 251fab8dff424abb95b2b381c7c924c3
+timeCreated: 1586386329