added some side channel tests (#3937)

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

 import uuid
+import pytest
+from mlagents_envs.side_channel.engine_configuration_channel import (
+    EngineConfigurationChannel,
+    EngineConfig,
+)
+from mlagents_envs.side_channel.environment_parameters_channel import (
+    EnvironmentParametersChannel,
+)
+from mlagents_envs.side_channel.stats_side_channel import (
+    StatsSideChannel,
+    StatsAggregationMethod,
+)
+from mlagents_envs.exception import (
+    UnitySideChannelException,
+    UnityCommunicationException,
+)
 
 
 class IntChannel(SideChannel):
     # Test reading with defaults
     assert [] == msg_in.read_float32_list()
     assert val == msg_in.read_float32_list(default_value=val)
+
+
+def test_engine_configuration():
+    sender = EngineConfigurationChannel()
+    # We use a raw bytes channel to interpred the data
+    receiver = RawBytesChannel(sender.channel_id)
+
+    config = EngineConfig.default_config()
+    sender.set_configuration(config)
+    data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+    UnityEnvironment._parse_side_channel_message({receiver.channel_id: receiver}, data)
+
+    received_data = receiver.get_and_clear_received_messages()
+    assert len(received_data) == 5  # 5 different messages one for each setting
+
+    sent_time_scale = 4.5
+    sender.set_configuration_parameters(time_scale=sent_time_scale)
+    data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+    UnityEnvironment._parse_side_channel_message({receiver.channel_id: receiver}, data)
+
+    message = IncomingMessage(receiver.get_and_clear_received_messages()[0])
+    message.read_int32()
+    time_scale = message.read_float32()
+    assert time_scale == sent_time_scale
+
+    with pytest.raises(UnitySideChannelException):
+        sender.set_configuration_parameters(width=None, height=42)
+
+    with pytest.raises(UnityCommunicationException):
+        # try to send data to the EngineConfigurationChannel
+        sender.set_configuration_parameters(time_scale=sent_time_scale)
+        data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+        UnityEnvironment._parse_side_channel_message(
+            {receiver.channel_id: sender}, data
+        )
+
+
+def test_environment_parameters():
+    sender = EnvironmentParametersChannel()
+    # We use a raw bytes channel to interpred the data
+    receiver = RawBytesChannel(sender.channel_id)
+
+    sender.set_float_parameter("param-1", 0.1)
+    data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+    UnityEnvironment._parse_side_channel_message({receiver.channel_id: receiver}, data)
+
+    message = IncomingMessage(receiver.get_and_clear_received_messages()[0])
+    key = message.read_string()
+    dtype = message.read_int32()
+    value = message.read_float32()
+    assert key == "param-1"
+    assert dtype == EnvironmentParametersChannel.EnvironmentDataTypes.FLOAT
+    assert value - 0.1 < 1e-8
+
+    sender.set_float_parameter("param-1", 0.1)
+    sender.set_float_parameter("param-2", 0.1)
+    sender.set_float_parameter("param-3", 0.1)
+
+    data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+    UnityEnvironment._parse_side_channel_message({receiver.channel_id: receiver}, data)
+
+    assert len(receiver.get_and_clear_received_messages()) == 3
+
+    with pytest.raises(UnityCommunicationException):
+        # try to send data to the EngineConfigurationChannel
+        sender.set_float_parameter("param-1", 0.1)
+        data = UnityEnvironment._generate_side_channel_data({sender.channel_id: sender})
+        UnityEnvironment._parse_side_channel_message(
+            {receiver.channel_id: sender}, data
+        )
+
+
+def test_stats_channel():
+    receiver = StatsSideChannel()
+    message = OutgoingMessage()
+    message.write_string("stats-1")
+    message.write_float32(42.0)
+    message.write_int32(1)  # corresponds to StatsAggregationMethod.MOST_RECENT
+
+    receiver.on_message_received(IncomingMessage(message.buffer))
+
+    stats = receiver.get_and_reset_stats()
+
+    assert len(stats) == 1
+    val, method = stats["stats-1"]
+    assert val - 42.0 < 1e-8
+    assert method == StatsAggregationMethod.MOST_RECENT