convert others, cleanup

.yamato/compressed-sensor-test.yml

   variables:
     UNITY_VERSION: {{ editor.version }}
   commands:
-    - python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
-    - python3 -u -m ml-agents.tests.yamato.setup_venv
-    - ./venv/bin/python ml-agents/tests/yamato/scripts/run_compressed_sensor.py --env=artifacts/testPlayer-TestGridCompressed
-    - ./venv/bin/python ml-agents/tests/yamato/scripts/run_compressed_sensor.py --env=artifacts/testPlayer-TestTextureCompressed
+    - |
+      sudo apt-get update && sudo apt-get install -y python3-venv
+      python3 -m venv venv && source venv/bin/activate
+      python -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
+      python -u -m ml-agents.tests.yamato.setup_venv
+      python ml-agents/tests/yamato/scripts/run_compressed_sensor.py --env=artifacts/testPlayer-TestGridCompressed
+      python ml-agents/tests/yamato/scripts/run_compressed_sensor.py --env=artifacts/testPlayer-TestTextureCompressed
   dependencies:
     - .yamato/standalone-build-test.yml#test_linux_standalone_{{ editor.version }}
   triggers:

.yamato/gym-interface-test.yml

   variables:
     UNITY_VERSION: {{ editor.version }}
   commands:
-    - python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
-    - python3 -u -m ml-agents.tests.yamato.setup_venv
-    - ./venv/bin/python ml-agents/tests/yamato/scripts/run_gym.py --env=artifacts/testPlayer-Basic
+    - |
+      sudo apt-get update && sudo apt-get install -y python3-venv
+      python3 -m venv venv && source venv/bin/activate
+      python -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
+      python -u -m ml-agents.tests.yamato.setup_venv
+      python ml-agents/tests/yamato/scripts/run_gym.py --env=artifacts/testPlayer-Basic
   dependencies:
     - .yamato/standalone-build-test.yml#test_linux_standalone_{{ editor.version }}
   triggers:

.yamato/python-ll-api-test.yml

   commands:
     - |
       sudo apt-get update && sudo apt-get install -y python3-venv
-      python3 -m venv venv && source venv/bin/activate && which python3
-      python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
-      python3 -u -m ml-agents.tests.yamato.setup_venv
-      ./venv/bin/python ml-agents/tests/yamato/scripts/run_llapi.py
-      ./venv/bin/python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-Basic
-      ./venv/bin/python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-WallJump
-      ./venv/bin/python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-Bouncer
+      python3 -m venv venv && source venv/bin/activate
+      python -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
+      python -u -m ml-agents.tests.yamato.setup_venv
+      python ml-agents/tests/yamato/scripts/run_llapi.py
+      python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-Basic
+      python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-WallJump
+      python ml-agents/tests/yamato/scripts/run_llapi.py --env=artifacts/testPlayer-Bouncer
+  dependencies:
+    - .yamato/standalone-build-test.yml#test_linux_standalone_{{ editor.version }}
+      (pull_request.target eq "master" OR
+      pull_request.target match "release.+") AND
       NOT pull_request.draft AND
       (pull_request.changes.any match "com.unity.ml-agents/**" OR
       pull_request.changes.any match "Project/**" OR

.yamato/training-int-tests.yml

   commands:
     - |
       sudo apt-get update && sudo apt-get install -y python3-venv
-      python3 -m venv venv && source venv/bin/activate && which python3
-      python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
-      python3 -m pip install unity-downloader-cli --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple --upgrade
+      python3 -m venv venv && source venv/bin/activate
+      python -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
+      python -m pip install unity-downloader-cli --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple --upgrade
-      python3 -u -m ml-agents.tests.yamato.training_int_tests
+      python -u -m ml-agents.tests.yamato.training_int_tests
+  dependencies:
+    - .yamato/standalone-build-test.yml#test_linux_standalone_{{ editor.version }}
+      (pull_request.target eq "master" OR
+      pull_request.target match "release.+") AND
       NOT pull_request.draft AND
       (pull_request.changes.any match "com.unity.ml-agents/**" OR
       pull_request.changes.any match "com.unity.ml-agents.extensions/**" OR
   variables:
     UNITY_VERSION: {{ editor_version }}
   commands:
-    - python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
-    # TODO remove the "--user" command and the path prefix when we can migrate away from the custom bokken image
-    - python3 -m pip install unity-downloader-cli --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple --upgrade --user
-    - /Users/bokken/Library/Python/3.7/bin/unity-downloader-cli -u {{ editor_version }} -c editor --wait --fast
-    # Backwards-compatibility tests.
-    # If we make a breaking change to the communication protocol, these will need
-    # to be disabled until the next release.
-    - python3 -u -m ml-agents.tests.yamato.standalone_build_tests --build-target=mac
-    - python -u -m ml-agents.tests.yamato.training_int_tests --python=0.16.0
-    - python -u -m ml-agents.tests.yamato.training_int_tests --csharp={{ csharp_backcompat_version }}
-  dependencies:
-    - .yamato/standalone-build-test.yml#test_linux_training_int_{{ editor_version }}
+    - |
+      python3 -m venv venv && source venv/bin/activate
+      python3 -m pip install pyyaml --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple
+      python3 -m pip install unity-downloader-cli --index-url https://artifactory.prd.it.unity3d.com/artifactory/api/pypi/pypi/simple --upgrade
+      unity-downloader-cli -u {{ editor_version }} -c editor --wait --fast
+      # Backwards-compatibility tests.
+      # If we make a breaking change to the communication protocol, these will need
+      # to be disabled until the next release.
+      python3 -u -m ml-agents.tests.yamato.standalone_build_tests --build-target=mac
+      python -u -m ml-agents.tests.yamato.training_int_tests --csharp={{ csharp_backcompat_version }}
+      deactivate
+      python3 -m venv venv_old && source venv_old/bin/activate
+      python -u -m ml-agents.tests.yamato.training_int_tests --python=0.16.0
   triggers:
     cancel_old_ci: true
     expression: |

ml-agents/tests/yamato/yamato_utils.py

 
 def init_venv(
     mlagents_python_version: str = None, extra_packages: Optional[List[str]] = None
-) -> str:
+) -> None:
-    Set up the virtual environment, and return the venv path.
+    Install the necessary packages for the venv
-    # Use a different venv path for different versions
-    venv_path = "venv"
-    if mlagents_python_version:
-        venv_path += "_" + mlagents_python_version
-
-    # Set up the venv and install mlagents
-    # if platform == "linux":
-    #     subprocess.check_call(
-    #         "sudo apt-get update && sudo apt-get install -y python3-venv", shell=True
-    #     )
-
-    if platform == "darwin":
-        subprocess.check_call(f"python3 -m venv {venv_path}", shell=True)
-
     pip_commands = ["--upgrade pip", "--upgrade setuptools"]
     if mlagents_python_version:
         # install from pypi
         subprocess.check_call(
             f"python3 -m pip install -q {cmd} {pip_index_url}", shell=True
         )
-    return venv_path
 
 
 def checkout_csharp_version(csharp_version):