Breaking change: require a stream to be set in TTYColoredFormatter

This avoids assuming where logs are being written, and ensures
everything works as expected when logs are redirected.

Closes #64.

colorlog/colorlog.py

@@ -197,7 +197,7 @@ class TTYColoredFormatter(ColoredFormatter):
 
     def __init__(self, *args, **kwargs):
         """Overwrite the `reset` argument to False if stream is not a TTY."""
-        self.stream = kwargs.pop('stream', sys.stdout)
+        self.stream = kwargs.pop('stream')
 
         # Both `reset` and `isatty` must be true to insert reset codes.
         kwargs['reset'] = kwargs.get('reset', True) and self.stream.isatty()

colorlog/tests/conftest.py

@@ -6,10 +6,17 @@
 import logging
 import sys
 
+import pytest
+
 import colorlog
 
-import pytest
-import testing_stream_handler
+
+class TestingStreamHandler(logging.StreamHandler):
+    """Raise errors to be caught by py.test instead of printing to stdout."""
+
+    def handleError(self, record):
+        _type, value, _traceback = sys.exc_info()
+        raise value
 
 
 def assert_log_message(log_function, message, capsys):
@@ -46,6 +53,7 @@ def function(logger, validator=None):
                 assert valid, "{!r} did not validate".format(line.strip())
 
         return lines
+
     return function
 
 
@@ -57,7 +65,7 @@ def function(*args, **kwargs):
 
         formatter = formatter_cls(*args, **kwargs)
 
-        stream = testing_stream_handler.TestingStreamHandler()
+        stream = TestingStreamHandler(stream=sys.stderr)
         stream.setLevel(logging.DEBUG)
         stream.setFormatter(formatter)
 
@@ -66,4 +74,5 @@ def function(*args, **kwargs):
         logger.addHandler(stream)
 
         return test_logger(logger, validator)
+
     return function

colorlog/tests/test_colorlog.py

@@ -89,13 +89,16 @@ def test_template_style(create_and_test_logger):
 
 
 def test_ttycolorlog(create_and_test_logger, monkeypatch):
-    monkeypatch.setattr(sys.stdout, 'isatty', lambda: True)
+    monkeypatch.setattr(sys.stderr, 'isatty', lambda: True)
     create_and_test_logger(
         formatter_class=colorlog.TTYColoredFormatter,
-        validator=lambda line: '\x1b[' in line)
+        validator=lambda line: '\x1b[' in line,
+        stream=sys.stderr)
+
 
 def test_ttycolorlog_notty(create_and_test_logger, monkeypatch):
-    monkeypatch.setattr(sys.stdout, 'isatty', lambda: False)
+    monkeypatch.setattr(sys.stderr, 'isatty', lambda: False)
     create_and_test_logger(
         formatter_class=colorlog.TTYColoredFormatter,
-        validator=lambda line: '\x1b[' not in line)
+        validator=lambda line: '\x1b[' not in line,
+        stream=sys.stderr)

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name='colorlog',
-    version='3.2.0',
+    version='4.0.0',
 
     description='Log formatting with colors!',
     long_description=open('README.md').read(),