Refactor test code's interpreter_selection_utils.py for better naming of util functions

tests/python/pants_test/backend/codegen/antlr/python/test_antlr_py_gen_integration.py

@@ -4,21 +4,21 @@
 
 from __future__ import absolute_import, division, print_function, unicode_literals
 
-from pants_test.backend.python.interpreter_selection_utils import skip_unless_python27
+from pants_test.backend.python.interpreter_selection_utils import skip_unless_python27_present
 from pants_test.pants_run_integration_test import PantsRunIntegrationTest
 
 
 class AntlrPyGenIntegrationTest(PantsRunIntegrationTest):
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   def test_antlr_py_gen_integration(self):
     result = self.run_pants(['run',
                              'testprojects/src/python/antlr:eval-bin',
                              '--run-py-args="123 * 321"'])
     self.assertEqual(0, result.returncode)
     self.assertIn('39483', result.stdout_data)
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   def test_python_invalid_antlr_grammar_fails(self):
     result = self.run_pants(['gen',
                              'testprojects/src/antlr/python/test:antlr_failure'])

tests/python/pants_test/backend/python/interpreter_selection_utils.py

@@ -10,9 +10,23 @@
 from pants.util.process_handler import subprocess
 
 
-PY_27 = '2.7'
+PY_2 = '2'
 PY_3 = '3'
+
+PY_26 = '2.6'
+PY_27 = '2.7'
+PY_34 = '3.4'
+PY_35 = '3.5'
 PY_36 = '3.6'
+PY_37 = '3.7'
+PY_38 = '3.8'
+
+
+def find_all_pythons_present(*versions):
+  """Return sorted list of all Python versions present on the system."""
+  if not versions:
+    versions = {PY_26, PY_27, PY_34, PY_35, PY_36, PY_37, PY_38}
+  return sorted(version for version in versions if has_python_version(version))
 
 
 def has_python_version(version):
@@ -36,12 +50,22 @@ def python_interpreter_path(version):
     command = ['python{}'.format(version), '-c', 'import sys; print(sys.executable)']
     py_path = subprocess.check_output(command).decode('utf-8').strip()
     return os.path.realpath(py_path)
-  except subprocess.CalledProcessError:
+  except (subprocess.CalledProcessError, FileNotFoundError):
     return None
 
 
-def skip_unless_pythons(*versions):
-  """A decorator that only runs the decorated test method if the specified pythons are present.
+def skip_unless_any_pythons_present(*versions):
+  """A decorator that only runs the decorated test method if any of the specified pythons are present.
+
+  :param string *versions: Python version strings, such as 2.7, 3.
+  """
+  if any(v for v in versions if has_python_version(v)):
+    return skipIf(False, 'At least one of the expected python versions found.')
+  return skipIf(True, 'Could not find at least one of the required pythons from {} on the system. Skipping.'.format(versions))
+
+
+def skip_unless_all_pythons_present(*versions):
+  """A decorator that only runs the decorated test method if all of the specified pythons are present.
 
   :param string *versions: Python version strings, such as 2.7, 3.
   """
@@ -56,26 +80,26 @@ def skip_unless_pythons(*versions):
     return skipIf(False, 'All required pythons present, continuing with test!')
 
 
-def skip_unless_python27(func):
+def skip_unless_python27_present(func):
   """A test skip decorator that only runs a test method if python2.7 is present."""
-  return skip_unless_pythons(PY_27)(func)
+  return skip_unless_all_pythons_present(PY_27)(func)
 
 
-def skip_unless_python3(func):
+def skip_unless_python3_present(func):
   """A test skip decorator that only runs a test method if python3 is present."""
-  return skip_unless_pythons(PY_3)(func)
+  return skip_unless_all_pythons_present(PY_3)(func)
 
 
-def skip_unless_python36(func):
+def skip_unless_python36_present(func):
   """A test skip decorator that only runs a test method if python3.6 is present."""
-  return skip_unless_pythons(PY_36)(func)
+  return skip_unless_all_pythons_present(PY_36)(func)
 
 
-def skip_unless_python27_and_python3(func):
+def skip_unless_python27_and_python3_present(func):
   """A test skip decorator that only runs a test method if python2.7 and python3 are present."""
-  return skip_unless_pythons(PY_27, PY_3)(func)
+  return skip_unless_all_pythons_present(PY_27, PY_3)(func)
 
 
-def skip_unless_python27_and_python36(func):
+def skip_unless_python27_and_python36_present(func):
   """A test skip decorator that only runs a test method if python2.7 and python3.6 are present."""
-  return skip_unless_pythons(PY_27, PY_36)(func)
+  return skip_unless_all_pythons_present(PY_27, PY_36)(func)

tests/python/pants_test/backend/python/tasks/test_interpreter_selection_integration.py

@@ -12,8 +12,9 @@
 
 from pants.util.contextutil import temporary_dir
 from pants.util.process_handler import subprocess
-from pants_test.backend.python.interpreter_selection_utils import (PY_3, PY_27, skip_unless_python3,
-                                                                   skip_unless_python27)
+from pants_test.backend.python.interpreter_selection_utils import (PY_3, PY_27,
+                                                                   skip_unless_python3_present,
+                                                                   skip_unless_python27_present)
 from pants_test.pants_run_integration_test import PantsRunIntegrationTest
 
 
@@ -50,11 +51,11 @@ def test_conflict_via_config(self):
     self.assertIn('Unable to detect a suitable interpreter for compatibilities',
                   pants_run.stdout_data)
 
-  @skip_unless_python3
+  @skip_unless_python3_present
   def test_select_3(self):
     self._test_version(PY_3)
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   def test_select_27(self):
     self._test_version(PY_27)
 

tests/python/pants_test/backend/python/tasks/test_pytest_run_integration.py

@@ -11,9 +11,9 @@
 from pants.util.contextutil import temporary_dir
 from pants_test.backend.python.interpreter_selection_utils import (PY_3, PY_27,
                                                                    python_interpreter_path,
-                                                                   skip_unless_python3,
-                                                                   skip_unless_python27,
-                                                                   skip_unless_python27_and_python3)
+                                                                   skip_unless_python3_present,
+                                                                   skip_unless_python27_and_python3_present,
+                                                                   skip_unless_python27_present)
 from pants_test.pants_run_integration_test import PantsRunIntegrationTest
 from pants_test.testutils.pexrc_util import setup_pexrc_with_pex_python_path
 
@@ -132,7 +132,7 @@ def test_pytest_with_profile(self):
   @unittest.skip(
     "Upgrade PEX: https://github.com/pantsbuild/pants/pull/7186. \
       NB: Ensure https://github.com/pantsbuild/pex/pull/678 is merged into the PEX release.")
-  @skip_unless_python27_and_python3
+  @skip_unless_python27_and_python3_present
   def test_pants_test_interpreter_selection_with_pexrc(self):
     """Test the pants test goal with intepreters selected from a PEX_PYTHON_PATH
     defined in a pexrc file on disk.
@@ -159,7 +159,7 @@ def test_pants_test_interpreter_selection_with_pexrc(self):
         )
         self.assert_success(pants_run_3)
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   def test_pants_test_interpreter_selection_with_option_2(self):
     """
     Test that the pants test goal properly constrains the SelectInterpreter task to Python 2
@@ -182,7 +182,7 @@ def test_pants_test_interpreter_selection_with_option_2(self):
       )
       self.assert_success(pants_run_2)
 
-  @skip_unless_python3
+  @skip_unless_python3_present
   def test_pants_test_interpreter_selection_with_option_3(self):
     """
     Test that the pants test goal properly constrains the SelectInterpreter task to Python 3

tests/python/pants_test/backend/python/tasks/test_python_run_integration.py

@@ -12,9 +12,9 @@
 from pants.util.contextutil import temporary_dir
 from pants_test.backend.python.interpreter_selection_utils import (PY_3, PY_27,
                                                                    python_interpreter_path,
-                                                                   skip_unless_python3,
-                                                                   skip_unless_python27,
-                                                                   skip_unless_python27_and_python3)
+                                                                   skip_unless_python3_present,
+                                                                   skip_unless_python27_and_python3_present,
+                                                                   skip_unless_python27_present)
 from pants_test.pants_run_integration_test import PantsRunIntegrationTest, ensure_daemon
 from pants_test.testutils.pexrc_util import setup_pexrc_with_pex_python_path
 
@@ -26,12 +26,12 @@ class PythonRunIntegrationTest(PantsRunIntegrationTest):
   def hermetic(cls):
     return True
 
-  @skip_unless_python3
+  @skip_unless_python3_present
   @ensure_daemon
   def test_run_3(self):
     self._run_version(PY_3)
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   @ensure_daemon
   def test_run_27(self):
     self._run_version(PY_27)
@@ -59,7 +59,7 @@ def _run_echo_version(self, version):
     pants_run = self.run_pants(command=command)
     return pants_run.stdout_data.splitlines()[0].strip()
 
-  @skip_unless_python27_and_python3
+  @skip_unless_python27_and_python3_present
   def test_run_27_and_then_3(self):
     with temporary_dir() as interpreters_cache:
       pants_ini_config = {'python-setup': {'interpreter_cache_dir': interpreters_cache}}
@@ -76,7 +76,7 @@ def test_run_27_and_then_3(self):
       )
       self.assert_success(pants_run_3)
 
-  @skip_unless_python3
+  @skip_unless_python3_present
   def test_run_3_by_option(self):
     with temporary_dir() as interpreters_cache:
       pants_ini_config = {'python-setup': {'interpreter_constraints': ["CPython>=2.7,<3.7"],
@@ -88,7 +88,7 @@ def test_run_3_by_option(self):
       )
       self.assert_success(pants_run_3)
 
-  @skip_unless_python27
+  @skip_unless_python27_present
   def test_run_2_by_option(self):
     with temporary_dir() as interpreters_cache:
       pants_ini_config = {'python-setup': {'interpreter_constraints': ["CPython>=2.7,<3.7"],
@@ -123,7 +123,7 @@ def test_get_env_var(self):
   @unittest.skip(
     "Upgrade PEX: https://github.com/pantsbuild/pants/pull/7186. \
       NB: Ensure https://github.com/pantsbuild/pex/pull/678 is merged into the PEX release.")
-  @skip_unless_python27_and_python3
+  @skip_unless_python27_and_python3_present
   def test_pants_run_interpreter_selection_with_pexrc(self):
     py27_path, py3_path = python_interpreter_path(PY_27), python_interpreter_path(PY_3)
     with setup_pexrc_with_pex_python_path([py27_path, py3_path]):
@@ -147,7 +147,7 @@ def test_pants_run_interpreter_selection_with_pexrc(self):
   @unittest.skip(
     "Upgrade PEX: https://github.com/pantsbuild/pants/pull/7186. \
       NB: Ensure https://github.com/pantsbuild/pex/pull/678 is merged into the PEX release.")
-  @skip_unless_python27_and_python3
+  @skip_unless_python27_and_python3_present
   def test_pants_binary_interpreter_selection_with_pexrc(self):
     py27_path, py3_path = python_interpreter_path(PY_27), python_interpreter_path(PY_3)
     with setup_pexrc_with_pex_python_path([py27_path, py3_path]):
@@ -181,7 +181,7 @@ def test_pants_binary_interpreter_selection_with_pexrc(self):
   @unittest.skip(
     "Upgrade PEX: https://github.com/pantsbuild/pants/pull/7186. \
       NB: Ensure https://github.com/pantsbuild/pex/pull/678 is merged into the PEX release.")
-  @skip_unless_python3
+  @skip_unless_python3_present
   def test_target_constraints_with_no_sources(self):
     with temporary_dir() as interpreters_cache:
       pants_ini_config = {

tests/python/pants_test/backend/python/tasks/test_setup_py.py

@@ -27,7 +27,7 @@
 from pants.util.collections_abc_backport import OrderedDict
 from pants.util.contextutil import environment_as, temporary_dir, temporary_file
 from pants.util.dirutil import safe_mkdir
-from pants_test.backend.python.interpreter_selection_utils import skip_unless_python36
+from pants_test.backend.python.interpreter_selection_utils import skip_unless_python36_present
 from pants_test.backend.python.tasks.python_task_test_base import PythonTaskTestBase
 from pants_test.subsystem.subsystem_util import init_subsystem
 
@@ -704,7 +704,7 @@ def assert_single_chroot(packages, namespace_packages, resources):
   def test_find_packages(self):
     self.assert_find_packages(py36=False)
 
-  @skip_unless_python36
+  @skip_unless_python36_present
   def test_find_packages_py3(self):
     self.assert_find_packages(py36=True)
 

tests/python/pants_test/backend/python/test_interpreter_cache.py

@@ -21,7 +21,7 @@
 from pants.util.dirutil import safe_mkdir
 from pants_test.backend.python.interpreter_selection_utils import (PY_27, PY_36,
                                                                    python_interpreter_path,
-                                                                   skip_unless_python27_and_python36)
+                                                                   skip_unless_python27_and_python36_present)
 from pants_test.test_base import TestBase
 from pants_test.testutils.pexrc_util import setup_pexrc_with_pex_python_path
 from pants_test.testutils.py2_compat import assertRegex
@@ -151,7 +151,7 @@ def test_setup_resolve_failure_cleanup(self):
       self.assertFalse('.tmp.' in ' '.join(os.listdir(cache_path)),
                        'interpreter cache path contains tmp dirs!')
 
-  @skip_unless_python27_and_python36
+  @skip_unless_python27_and_python36_present
   def test_interpereter_cache_setup_using_pex_python_paths(self):
     """Test cache setup using interpreters from a mocked PEX_PYTHON_PATH."""
     py27_path, py36_path = python_interpreter_path(PY_27), python_interpreter_path(PY_36)