WIP: PYTEST_FORCE_COLOR, NO_COLOR

src/_pytest/_io/__init__.py

@@ -12,13 +12,21 @@
 
 
 def use_markup(file: "TextIO") -> bool:
+    # Backward compatibility with pylib: handle PY_COLORS={0,1} only.
     val = os.getenv("PY_COLORS")
+    if val in ("0", "1"):
+        return val == "1"
+
+    # PYTEST_FORCE_COLOR: handled as boolean.
+    val = os.getenv("PYTEST_FORCE_COLOR")
     if val is not None:
         from _pytest.config import _strtobool
 
         return _strtobool(val)
 
-    from _pytest.assertion.util import _running_on_ci
+    # NO_COLOR: disable markup with any value (https://no-color.org/).
+    if "NO_COLOR" in os.environ:
+        return False
 
     if _running_on_ci():
         return True
@@ -103,3 +111,7 @@ def _highlight(self, source):
             return source
         else:
             return highlight(source, PythonLexer(), TerminalFormatter(bg="dark"))
+
+
+def _running_on_ci():
+    return os.environ.get("CI", "").lower() == "true" or "BUILD_NUMBER" in os.environ

src/_pytest/assertion/truncate.py

@@ -5,7 +5,6 @@
 ~8 terminal lines, unless running in "-vv" mode or running on CI.
 """
 from ..compat import TYPE_CHECKING
-from _pytest.assertion.util import _running_on_ci
 
 if TYPE_CHECKING:
     from typing import List
@@ -28,7 +27,12 @@ def _should_truncate(config: "Config") -> bool:
     level = config.getini("assert_truncate_level")  # type: str
     verbose = config.option.verbose  # type: int
     if level == "auto":
-        return verbose < 2 and not _running_on_ci()
+        if verbose >= 2:
+            return False
+
+        from _pytest._io import _running_on_ci
+
+        return not _running_on_ci()
     return int(level) > verbose
 
 

src/_pytest/assertion/util.py

@@ -1,7 +1,6 @@
 """Utilities for assertion debugging"""
 import collections.abc
 import itertools
-import os
 import pprint
 import re
 from typing import AbstractSet
@@ -534,7 +533,3 @@ def _notin_text(term: str, text: str, verbose: int = 0) -> List[str]:
         "? " + indent + marker,
     ]
     return newdiff
-
-
-def _running_on_ci():
-    return os.environ.get("CI", "").lower() == "true" or "BUILD_NUMBER" in os.environ

src/_pytest/terminal.py

@@ -34,7 +34,6 @@
 from _pytest import nodes
 from _pytest._code.code import ExceptionInfo
 from _pytest._code.code import ReprFileLocation
-from _pytest.assertion.util import _running_on_ci
 from _pytest.compat import order_preserving_dict
 from _pytest.compat import shell_quote
 from _pytest.compat import TYPE_CHECKING
@@ -1214,10 +1213,15 @@ def short_test_summary(self) -> None:
         if not self.reportchars:
             return
 
-        if not self.isatty or _running_on_ci():
+        if not self.isatty:
             termwidth = None
         else:
-            termwidth = self._tw.fullwidth
+            from _pytest._io import _running_on_ci
+
+            if _running_on_ci():
+                termwidth = None
+            else:
+                termwidth = self._tw.fullwidth
 
         def show_simple(stat, lines: List[str]) -> None:
             failed = self.stats.get(stat, [])