DS-4784 Create tests for Python part of tables support

Exclude polars from testing in Python2.7
Exclude polars for testing in Python 2.7 in advance from test_common.py

GitOrigin-RevId: 692d6bacb365665e618d650b7b739e0d86372ad1

python/helpers/pydev/pydev_tests_tables/pytest.ini

@@ -1,3 +1,5 @@
 [pytest]
 addopts=-vv
-python_files = test_*.py
+python_files = test_*.py
+# If you want to exclude some tests from running in Python 2.7 you should use the corresponding decorator
+# @pytest.mark.skipif(sys.version_info < (3, 0), reason="Not supported in Python 2.7")

python/helpers/pydev/pydev_tests_tables/test_common.py

@@ -8,6 +8,7 @@ We check:
 """
 
 import os
+import sys
 import pytest
 import inspect
 import importlib
@@ -21,6 +22,9 @@ def setup_tables_modules():
     for _, _, files in os.walk(pydevd_tables_path):
         for file in files:
             if file.endswith('py') and file != '__init__.py':
+                if sys.version_info < (3, 0) and 'polars' in file:
+                    # we don't need to test polars for python 2.7
+                    continue
                 tables_files.append(file)
                 module_name = '_pydevd_bundle.tables.' + file.replace('.py', '')
                 tables_modules.append(importlib.import_module(module_name))

python/helpers/pydev/pydev_tests_tables/tox.ini

@@ -1,16 +1,17 @@
 [tox]
 envlist = python2.7, python3.8, python3.9
-isolated_build = true
+isolated_build = True
 skipsdist = True
 
 [testenv]
+description = run unit tests in 3 different Python versions
 deps =
-    pytest
-    teamcity-messages
-    pandas
-    polars
-    IPython
-commands =
-    pytest -s
+    python2.7: pytest teamcity-messages pandas IPython
+    python3.8: pytest teamcity-messages pandas IPython polars
+    python3.9: pytest teamcity-messages pandas IPython polars
+
+whitelist_externals = pytest
+commands = pytest -s
+
 setenv = PYTHONPATH = {toxinidir}/../third_party/thriftpy
 passenv = TEAMCITY_VERSION