Fixed handling of NO_COLOR environment variable.

Author: kmvanbrunt

cmd2/pt_utils.py

@@ -79,7 +79,7 @@ def pt_filter_style(text: str | ANSI) -> str | ANSI:
 
 def pt_resolve_color_depth() -> ColorDepth:
     """Determine the prompt-toolkit ColorDepth based on NO_COLOR and ru.ALLOW_STYLE."""
-    if "NO_COLOR" in os.environ or ru.ALLOW_STYLE == ru.AllowStyle.NEVER:
+    if os.environ.get("NO_COLOR") or ru.ALLOW_STYLE == ru.AllowStyle.NEVER:
         return ColorDepth.DEPTH_1_BIT
     return ColorDepth.TRUE_COLOR
 

tests/test_pt_utils.py

@@ -100,15 +100,15 @@ def test_pt_filter_style_never() -> None:
 
 @with_ansi_style(ru.AllowStyle.ALWAYS)
 def test_pt_resolve_color_depth_always(monkeypatch) -> None:
-    # Ensure any host NO_COLOR environment variable doesn't affect the test
+    # Clear NO_COLOR to ensure colors are not suppressed
     monkeypatch.delenv("NO_COLOR", raising=False)
     assert pt_resolve_color_depth() == ColorDepth.TRUE_COLOR
 
 
 @with_ansi_style(ru.AllowStyle.TERMINAL)
 def test_pt_resolve_color_depth_terminal(monkeypatch) -> None:
-    # Ensure any host NO_COLOR environment variable doesn't affect the test
-    monkeypatch.delenv("NO_COLOR", raising=False)
+    # Mock NO_COLOR to an empty string to ensure colors are not suppressed
+    monkeypatch.setenv("NO_COLOR", "")
     assert pt_resolve_color_depth() == ColorDepth.TRUE_COLOR
 
 
@@ -121,7 +121,7 @@ def test_pt_resolve_color_depth_never(monkeypatch) -> None:
 
 @with_ansi_style(ru.AllowStyle.ALWAYS)
 def test_pt_resolve_color_depth_no_color(monkeypatch) -> None:
-    # Mock NO_COLOR=1 to ensure colors are suppressed
+    # Mock NO_COLOR to ensure colors are suppressed
     monkeypatch.setenv("NO_COLOR", "1")
     assert pt_resolve_color_depth() == ColorDepth.DEPTH_1_BIT