Pytest does not work with error.

[zhouwangyang]

Environment data

VS Code version: 1.38-insider
Extension version (available under the Extensions sidebar): python 2019.9.33413-rc

Expected behaviour

Tests are discovered (as shown by code lenses on each test) and run successfully.

Actual behaviour

An error happened
Error: TypeError: cannot read property '$' of undefined

Steps to reproduce:

1. Open folder pytests in VSC
2. Create test.py and tyiping code:
   def test_passing():
   assert 42==42
   def test_failure():
   assert 42==-13
3. pytest installed in current environment.
   4.Run command: "Run All Tests", ensure:
   a. Click "Enable and configure a test framework"
   b. Select "pytest" and next ". Root directory"

repro steps:
pytest.zip

[Flamefire]

See #6990

[ericsnowcurrently]

This is a duplicate of #6990.