compat: a few minor cleanups

src/_pytest/assertion/truncate.py

@@ -6,7 +6,7 @@
 
 from __future__ import annotations
 
-from _pytest.assertion import util
+from _pytest.compat import running_on_ci
 from _pytest.config import Config
 from _pytest.nodes import Item
 
@@ -43,7 +43,7 @@ def _get_truncation_parameters(item: Item) -> tuple[bool, int, int]:
 
     verbose = item.config.get_verbosity(Config.VERBOSITY_ASSERTIONS)
 
-    should_truncate = verbose < 2 and not util.running_on_ci()
+    should_truncate = verbose < 2 and not running_on_ci()
     should_truncate = should_truncate and (max_lines > 0 or max_chars > 0)
 
     return should_truncate, max_lines, max_chars

src/_pytest/assertion/util.py

@@ -9,7 +9,6 @@
 from collections.abc import Mapping
 from collections.abc import Sequence
 from collections.abc import Set as AbstractSet
-import os
 import pprint
 from typing import Any
 from typing import Literal
@@ -21,6 +20,7 @@
 from _pytest._io.pprint import PrettyPrinter
 from _pytest._io.saferepr import saferepr
 from _pytest._io.saferepr import saferepr_unlimited
+from _pytest.compat import running_on_ci
 from _pytest.config import Config
 
 
@@ -613,9 +613,3 @@ def _notin_text(term: str, text: str, verbose: int = 0) -> list[str]:
         else:
             newdiff.append(line)
     return newdiff
-
-
-def running_on_ci() -> bool:
-    """Check if we're currently running on a CI system."""
-    env_vars = ["CI", "BUILD_NUMBER"]
-    return any(var in os.environ for var in env_vars)

src/_pytest/compat.py

@@ -1,5 +1,5 @@
 # mypy: allow-untyped-defs
-"""Python version compatibility code."""
+"""Python version compatibility code and random general utilities."""
 
 from __future__ import annotations
 
@@ -278,39 +278,12 @@ def get_user_id() -> int | None:
         return uid if uid != ERROR else None
 
 
-# Perform exhaustiveness checking.
-#
-# Consider this example:
-#
-#     MyUnion = Union[int, str]
-#
-#     def handle(x: MyUnion) -> int {
-#         if isinstance(x, int):
-#             return 1
-#         elif isinstance(x, str):
-#             return 2
-#         else:
-#             raise Exception('unreachable')
-#
-# Now suppose we add a new variant:
-#
-#     MyUnion = Union[int, str, bytes]
-#
-# After doing this, we must remember ourselves to go and update the handle
-# function to handle the new variant.
-#
-# With `assert_never` we can do better:
-#
-#     // raise Exception('unreachable')
-#     return assert_never(x)
-#
-# Now, if we forget to handle the new variant, the type-checker will emit a
-# compile-time error, instead of the runtime error we would have gotten
-# previously.
-#
-# This also work for Enums (if you use `is` to compare) and Literals.
-def assert_never(value: NoReturn) -> NoReturn:
-    assert False, f"Unhandled value: {value} ({type(value).__name__})"
+if sys.version_info >= (3, 11):
+    from typing import assert_never
+else:
+
+    def assert_never(value: NoReturn) -> NoReturn:
+        assert False, f"Unhandled value: {value} ({type(value).__name__})"
 
 
 class CallableBool:
@@ -331,3 +304,9 @@ def __bool__(self) -> bool:
 
     def __call__(self) -> bool:
         return self._value
+
+
+def running_on_ci() -> bool:
+    """Check if we're currently running on a CI system."""
+    env_vars = ["CI", "BUILD_NUMBER"]
+    return any(var in os.environ for var in env_vars)

src/_pytest/terminal.py

@@ -39,7 +39,7 @@
 from _pytest._io import TerminalWriter
 from _pytest._io.wcwidth import wcswidth
 import _pytest._version
-from _pytest.assertion.util import running_on_ci
+from _pytest.compat import running_on_ci
 from _pytest.config import _PluggyPlugin
 from _pytest.config import Config
 from _pytest.config import ExitCode

testing/test_collection.py

@@ -10,7 +10,7 @@
 import tempfile
 import textwrap
 
-from _pytest.assertion.util import running_on_ci
+from _pytest.compat import running_on_ci
 from _pytest.config import ExitCode
 from _pytest.fixtures import FixtureRequest
 from _pytest.main import _in_venv