Test colored tracebacks

Author: borntyping

colorlog/formatter.py

@@ -140,28 +140,28 @@ def _escape_code_map(self, item: str) -> EscapeCodes:
         """
         Build a map of keys to escape codes for use in message formatting.
 
-        If _blank_escape_codes() returns True, all values will be an empty string.
+        If _color() returns False, all values will be an empty string.
         """
         codes = {**colorlog.escape_codes.escape_codes}
         codes.setdefault("log_color", self._get_escape_code(self.log_colors, item))
         for name, colors in self.secondary_log_colors.items():
             codes.setdefault("%s_log_color" % name, self._get_escape_code(colors, item))
-        if self._blank_escape_codes():
+        if not self._colorize():
             codes = {key: "" for key in codes.keys()}
         return codes
 
-    def _blank_escape_codes(self):
-        """Return True if we should be prevented from printing escape codes."""
+    def _colorize(self):
+        """Return False if we should be prevented from printing escape codes."""
         if self.force_color or "FORCE_COLOR" in os.environ:
-            return False
+            return True
 
         if self.no_color or "NO_COLOR" in os.environ:
-            return True
+            return False
 
         if self.stream is not None and not self.stream.isatty():
-            return True
+            return False
 
-        return False
+        return True
 
     @staticmethod
     def _get_escape_code(log_colors: LogColors, item: str) -> str:
@@ -179,21 +179,18 @@ def _append_reset(self, message: str, escapes: EscapeCodes) -> str:
 
     if sys.version_info >= (3, 13):
 
-        def formatException(self, ei):
-            """Format and return the specified exception information as a string."""
-            # This is a copy of logging.Formatter.formatException that passes in
-            # an appropriate value for colorize to print_exception.
+        def formatException(self, ei) -> str:
+            """
+            Format and return the specified exception information as a string.
+
+            This is a copy of logging.Formatter.formatException that passes in
+            an appropriate value for colorize to print_exception.
+            """
+            kwargs = dict(colorize=self._colorize())
 
             sio = io.StringIO()
             tb = ei[2]
-            traceback.print_exception(
-                ei[0],
-                ei[1],
-                tb,
-                limit=None,
-                file=sio,
-                colorize=not self._blank_escape_codes(),
-            )
+            traceback.print_exception(ei[0], ei[1], tb, limit=None, file=sio, **kwargs)
             s = sio.getvalue()
             sio.close()
             if s[-1:] == "\n":

colorlog/tests/test_colorlog.py

@@ -1,6 +1,9 @@
 """Test the colorlog.colorlog module."""
 
 import sys
+import unittest.mock
+
+import pytest
 
 import colorlog
 
@@ -114,3 +117,20 @@ def test_ttycolorlog_notty(create_and_test_logger, monkeypatch):
         validator=lambda line: "\x1b[" not in line,
         stream=sys.stderr,
     )
+
+
+if sys.version_info >= (3, 13):
+
+    @pytest.mark.parametrize("tty", [True, False])
+    def test_formatException(tty: bool, monkeypatch):
+        stream = unittest.mock.Mock()
+        stream.isatty = unittest.mock.Mock(return_value=tty)
+
+        formatter = colorlog.ColoredFormatter(stream=stream)
+        try:
+            raise KeyError("test")
+        except KeyError:
+            ei = sys.exc_info()
+            text = formatter.formatException(ei)
+
+        assert ("\x1b[" in text) == tty