Bump default Pytest to 4.6 and add warning for future change to Pytest 5

pants.ini

@@ -398,6 +398,13 @@ interpreter_cache_dir: %(pants_bootstrapdir)s/python_cache/interpreters
 resolver_cache_dir: %(pants_bootstrapdir)s/python_cache/requirements
 
 
+[pytest]
+version: pytest>=5.2.4
+# TODO(#8651): We need this until we switch to implicit namespace packages so that pytest-cov
+#  understands our __init__ files. NB: this version matches 3rdparty/python/requirements.txt.
+pytest_plugins: +["setuptools==40.6.3"]
+
+
 [test.pytest]
 fast: false
 chroot: true

src/python/pants/backend/python/rules/python_test_runner_integration_test.py

@@ -67,7 +67,7 @@ def test_passing_test(self):
 
         pants/dummies/test_pass.py .                                             [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:passing_target                          .....   SUCCESS
@@ -98,7 +98,7 @@ def test_fail():
         E     assert False
 
         pants/dummies/test_fail.py:2: AssertionError
-        =========================== 1 failed in SOME_TEXT ===========================
+        ============================== 1 failed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:failing_target                          .....   FAILURE
@@ -130,7 +130,7 @@ def test_fail():
         E     assert False
 
         pants/dummies/test_fail.py:2: AssertionError
-        =========================== 1 failed in SOME_TEXT ===========================
+        ============================== 1 failed in SOME_TEXT ===============================
 
         testprojects/tests/python/pants/dummies:passing_target stdout:
         ============================= test session starts ==============================
@@ -141,7 +141,7 @@ def test_fail():
 
         pants/dummies/test_pass.py .                                             [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:failing_target                          .....   FAILURE
@@ -165,7 +165,7 @@ def test_source_dep_absolute_import(self):
 
         pants/dummies/test_with_source_dep_absolute_import.py .                  [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:target_with_source_dep_absolute_import  .....   SUCCESS
@@ -188,7 +188,7 @@ def test_source_dep_relative_import(self):
 
         pants/dummies/test_with_source_dep_relative_import.py .                  [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:target_with_source_dep_relative_import  .....   SUCCESS
@@ -211,7 +211,7 @@ def test_thirdparty_dep(self):
 
         pants/dummies/test_with_thirdparty_dep.py .                              [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:target_with_thirdparty_dep              .....   SUCCESS
@@ -234,7 +234,7 @@ def test_transitive_dep(self):
 
         pants/dummies/test_with_transitive_dep.py .                              [100%]
 
-        =========================== 1 passed in SOME_TEXT ===========================
+        ============================== 1 passed in SOME_TEXT ===============================
 
 
         testprojects/tests/python/pants/dummies:target_with_transitive_dep              .....   SUCCESS

src/python/pants/backend/python/subsystems/pytest.py

@@ -3,6 +3,7 @@
 
 from typing import List, Tuple
 
+from pants.base.deprecated import deprecated_conditional
 from pants.subsystem.subsystem import Subsystem
 
 
@@ -12,28 +13,29 @@ class PyTest(Subsystem):
   @classmethod
   def register_options(cls, register):
     super().register_options(register)
-    register('--version', default='pytest>=3.0.7,<3.7', help="Requirement string for Pytest.")
+    register('--version', default='pytest>=4.6.6,<4.7', help="Requirement string for Pytest.")
     register(
       '--pytest-plugins',
       type=list,
       default=[
-        'pytest-timeout>=1.2,<1.3',
-        'pytest-cov>=2.4,<2.5',
-        "unittest2>=0.6.0,<=1.9.0 ; python_version<'3'"
+        'pytest-timeout>=1.3.3,<1.4',
+        'pytest-cov>=2.8.1,<3',
+        "unittest2>=1.1.0 ; python_version<'3'",
+        "more-itertools<6.0.0 ; python_version<'3'",
       ],
       help="Requirement strings for any plugins or additional requirements you'd like to use.",
     )
-    register('--requirements', advanced=True, default='pytest>=3.0.7,<3.7',
+    register('--requirements', advanced=True, default='pytest>=4.6.6,<4.7',
              help='Requirements string for the pytest library.',
              removal_version="1.25.0.dev0", removal_hint="Use --version instead.")
-    register('--timeout-requirements', advanced=True, default='pytest-timeout>=1.2,<1.3',
+    register('--timeout-requirements', advanced=True, default='pytest-timeout>=1.3.3,<1.4',
              help='Requirements string for the pytest-timeout library.',
              removal_version="1.25.0.dev0", removal_hint="Use --pytest-plugins instead.")
-    register('--cov-requirements', advanced=True, default='pytest-cov>=2.4,<2.5',
+    register('--cov-requirements', advanced=True, default='pytest-cov>=2.8.1,<3',
              help='Requirements string for the pytest-cov library.',
              removal_version="1.25.0.dev0", removal_hint="Use --pytest-plugins instead.")
     register('--unittest2-requirements', advanced=True,
-             default="unittest2>=0.6.0,<=1.9.0 ; python_version<'3'",
+             default="unittest2>=1.1.0 ; python_version<'3'",
              help='Requirements string for the unittest2 library, which some python versions '
                   'may need.',
              removal_version="1.25.0.dev0", removal_hint="Use --pytest-plugins instead.")
@@ -61,6 +63,19 @@ def format_opts(opt_symbol_names: List[str]) -> str:
         f"deprecated style: `{format_opts(configured_deprecated_option)}`.\nPlease use only one "
         f"approach (preferably the new approach of `--version` and `--pytest-plugins`)."
       )
+
+    deprecated_conditional(
+      lambda: opts.is_default("version") and opts.is_default("requirements"),
+      removal_version="1.25.0.dev2",
+      entity_description="Pants defaulting to a Python 2-compatible Pytest version",
+      hint_message="Pants will soon start defaulting to Pytest 5.x, which no longer supports "
+                   "running tests with Python 2. In preparation for this change, you should "
+                   "explicitly set what version of Pytest to use in your `pants.ini` under the "
+                   "section `pytest`.\n\nIf you need to keep running tests with Python 2, set "
+                   "`version` to `pytest>=4.6.6,<4.7` (the current default). If you don't have any "
+                   "tests with Python 2 and want the newest Pytest, set `version` to "
+                   "`pytest>=5.2.4`."
+    )
     if configured_deprecated_option:
       return (
         "more-itertools<6.0.0 ; python_version<'3'",
@@ -69,8 +84,4 @@ def format_opts(opt_symbol_names: List[str]) -> str:
         opts.cov_requirements,
         opts.unittest2_requirements,
       )
-    return (
-      "more-itertools<6.0.0 ; python_version<'3'",
-      opts.version,
-      *opts.pytest_plugins
-    )
+    return (opts.version, *opts.pytest_plugins)

src/python/pants/testutil/base/context_utils.py

@@ -37,10 +37,12 @@ class DummyWorkUnit:
    """
 
     def output(self, name):
-      return sys.stderr
+      return sys.stderr.buffer
 
     def set_outcome(self, outcome):
-      return sys.stderr.write('\nWorkUnit outcome: {}\n'.format(WorkUnit.outcome_string(outcome)))
+      return sys.stderr.buffer.write(
+        f'\nWorkUnit outcome: {WorkUnit.outcome_string(outcome)}\n'.encode()
+      )
 
   class DummyRunTracker:
     """A runtracker stand-in that does no actual tracking."""

testprojects/tests/python/pants/dummies/BUILD

@@ -33,7 +33,7 @@ python_tests(
   name = 'target_with_thirdparty_dep',
   sources = ['test_with_thirdparty_dep.py'],
   dependencies = [
-    '3rdparty/python:ansicolors',
+    '3rdparty/python:typing-extensions',
   ],
 )
 

testprojects/tests/python/pants/dummies/test_with_thirdparty_dep.py

@@ -1,8 +1,9 @@
 # Copyright 2018 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-from colors import red, strip_color
+from typing_extensions import Literal
 
 
 def test_f():
-  assert strip_color(red("foo")) == "foo"
+  assert Literal[1] == Literal[1]
+  assert Literal[1] != Literal[2]

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

@@ -141,6 +141,10 @@ def test_pants_test_interpreter_selection_with_pexrc(self):
           'python-setup': {
             'interpreter_cache_dir': interpreters_cache,
             'interpreter_search_paths': ['<PEXRC>'],
+          },
+          # NB: we pin Pytest to 4.6 to ensure Pytest still works with Python 2.
+          'pytest': {
+            'version': 'pytest==4.6.6',
           }
         }
         pants_run_27 = self.run_pants(
@@ -167,6 +171,10 @@ def test_pants_test_interpreter_selection_with_option_2(self):
         'python-setup': {
           'interpreter_constraints': ['CPython>=2.7,<4'],
           'interpreter_cache_dir': interpreters_cache,
+        },
+        # NB: we pin Pytest to 4.6 to ensure Pytest still works with Python 2.
+        'pytest': {
+          'version': 'pytest==4.6.6',
         }
       }
       pants_run_2 = self.run_pants(