Invalid python sys path to directory with tested file on Windows #2673

Description

UnitTestBot generates tests with invalid sys.path on Windows when "Test sources root" coincides with file under test.

To Reproduce

Steps to reproduce the behavior:

1. Run a python project in Pycharm
2. Use plugin to generate tests and set a path to directory with tested file in the field "Test sources root"
3. Open the generated test

Expected behavior

Valid tests with correct sys paths

Actual behavior

Valid tests with incorrect sys path (sys.path.append(os.path.dirname(__file__) + r'\')). The problem is that python raw-string cannot end in backslash.

Visual proofs (screenshots, logs, images)
Tested function

UTBot window

sys.path

Environment

Windows + specified above "Test sources root"

Solutions

1. Replace backslash at the end by "\."
2. Remove backslash at the end
3. Skip sys.path if it coincides with tested function directory