SG-45235 Remove obsolete Python 2-era vendored unit-test dependency system

.gitattributes

@@ -17,6 +17,3 @@
 # The git executable expects packed-refs to always have LF line endings, even on
 # Windows.
 **/packed-refs text eol=lf
-
-# We don't want CRLF conversion or any automatic change in there
-tests/python/third_party/** binary

.gitignore

@@ -34,7 +34,6 @@ pip-log.txt
 coverage.xml
 coverage_html_report
 htmlcov
-tests/python/third_party
 
 #Translations
 *.mo

tests/README.md

@@ -1,47 +1,25 @@
 Readme for Tank core tests
 ==========================
 
-Required packages
------------------
-To install the required dependencies, just run the following command on the `python` directory.
-
-```shell
-cd python
-./upgrade_third_party.sh
-```
-
-Packages will be installed under `tests/python/third_party`
-
 Running the test suite
 -----------------------
-To run the tests on Windows run the `run_tests.bat`. Also you need to run it as `admin` in `powershell`
-with unrestricted execution policy (`Set-ExecutionPolicy Unrestricted`).
-
-To run on Linux or macOS, run the script `run_tests.sh`.
-
-Add `-h` to see options.
-Add `--with-coverage` to enable coverage.
-
-To run specific test(s), specify module, or module.class or module.class.test:
+The tests run with [pytest](https://docs.pytest.org/) through
+[tk-toolchain](https://github.com/shotgunsoftware/tk-toolchain). Install
+`tk-toolchain` and run `pytest` from the repository root:
 
 ```shell
-run_tests.sh test_tank_content.TestValidate.test_valid_path
+pip install git+https://github.com/shotgunsoftware/tk-toolchain.git
+pytest
 ```
 
-To run all the tests from a specific file, you can specify both the module or file path:
-
-```shell
-./run_tests.sh tank_module_test.test_module
-```
+To run a specific test file, class, or test:
 
 ```shell
-./run_tests.sh tank_module_test/test_module.py
+pytest tests/core_tests/test_api.py
+pytest tests/core_tests/test_api.py::TestApi::test_something
 ```
 
-Compile sources with Python 3
------------------------------
-To make sure the tank source code can be compiled with Python 3, run the `compile_python3.*` scripts. Note that the unit tests cannot
-be executed right now with Python 3.
+Add `--cov` to enable coverage.
 
 Test suite layout
 -----------------

tests/integration_tests/run_integration_tests.py

@@ -33,7 +33,6 @@ def main():
     environ["PYTHONPATH"] = os.path.pathsep.join(
         [
             os.path.join(current_folder, "..", "python"),
-            os.path.join(current_folder, "..", "python", "third_party"),
             os.path.join(current_folder, "..", "..", "python"),
         ]
     )