Merge pull request #4950 from blueyed/capture

Revisit capturing module: repr, doc fixes, minor

src/_pytest/capture.py

@@ -91,6 +91,13 @@ class CaptureManager(object):
         self._global_capturing = None
         self._current_item = None
 
+    def __repr__(self):
+        return "<CaptureManager _method=%r _global_capturing=%r _current_item=%r>" % (
+            self._method,
+            self._global_capturing,
+            self._current_item,
+        )
+
     def _getcapture(self, method):
         if method == "fd":
             return MultiCapture(out=True, err=True, Capture=FDCapture)
@@ -98,8 +105,7 @@ class CaptureManager(object):
             return MultiCapture(out=True, err=True, Capture=SysCapture)
         elif method == "no":
             return MultiCapture(out=False, err=False, in_=False)
-        else:
+        raise ValueError("unknown capturing method: %r" % method)  # pragma: no cover
-            raise ValueError("unknown capturing method: %r" % method)
 
     # Global capturing control
 
@@ -161,8 +167,8 @@ class CaptureManager(object):
 
     @contextlib.contextmanager
     def global_and_fixture_disabled(self):
-        """Context manager to temporarily disables global and current fixture capturing."""
+        """Context manager to temporarily disable global and current fixture capturing."""
-        # Need to undo local capsys-et-al if exists before disabling global capture
+        # Need to undo local capsys-et-al if it exists before disabling global capture.
         self.suspend_fixture(self._current_item)
         self.suspend_global_capture(in_=False)
         try:
@@ -247,10 +253,11 @@ def _ensure_only_one_capture_fixture(request, name):
 
 @pytest.fixture
 def capsys(request):
-    """Enable capturing of writes to ``sys.stdout`` and ``sys.stderr`` and make
+    """Enable text capturing of writes to ``sys.stdout`` and ``sys.stderr``.
-    captured output available via ``capsys.readouterr()`` method calls
+
-    which return a ``(out, err)`` namedtuple.  ``out`` and ``err`` will be ``text``
+    The captured output is made available via ``capsys.readouterr()`` method
-    objects.
+    calls, which return a ``(out, err)`` namedtuple.
+    ``out`` and ``err`` will be ``text`` objects.
     """
     _ensure_only_one_capture_fixture(request, "capsys")
     with _install_capture_fixture_on_item(request, SysCapture) as fixture:
@@ -259,26 +266,28 @@ def capsys(request):
 
 @pytest.fixture
 def capsysbinary(request):
-    """Enable capturing of writes to ``sys.stdout`` and ``sys.stderr`` and make
+    """Enable bytes capturing of writes to ``sys.stdout`` and ``sys.stderr``.
-    captured output available via ``capsys.readouterr()`` method calls
+
-    which return a ``(out, err)`` tuple.  ``out`` and ``err`` will be ``bytes``
+    The captured output is made available via ``capsysbinary.readouterr()``
-    objects.
+    method calls, which return a ``(out, err)`` namedtuple.
+    ``out`` and ``err`` will be ``bytes`` objects.
     """
     _ensure_only_one_capture_fixture(request, "capsysbinary")
     # Currently, the implementation uses the python3 specific `.buffer`
     # property of CaptureIO.
     if sys.version_info < (3,):
-        raise request.raiseerror("capsysbinary is only supported on python 3")
+        raise request.raiseerror("capsysbinary is only supported on Python 3")
     with _install_capture_fixture_on_item(request, SysCaptureBinary) as fixture:
         yield fixture
 
 
 @pytest.fixture
 def capfd(request):
-    """Enable capturing of writes to file descriptors ``1`` and ``2`` and make
+    """Enable text capturing of writes to file descriptors ``1`` and ``2``.
-    captured output available via ``capfd.readouterr()`` method calls
+
-    which return a ``(out, err)`` tuple.  ``out`` and ``err`` will be ``text``
+    The captured output is made available via ``capfd.readouterr()`` method
-    objects.
+    calls, which return a ``(out, err)`` namedtuple.
+    ``out`` and ``err`` will be ``text`` objects.
     """
     _ensure_only_one_capture_fixture(request, "capfd")
     if not hasattr(os, "dup"):
@@ -291,10 +300,11 @@ def capfd(request):
 
 @pytest.fixture
 def capfdbinary(request):
-    """Enable capturing of write to file descriptors 1 and 2 and make
+    """Enable bytes capturing of writes to file descriptors ``1`` and ``2``.
-    captured output available via ``capfdbinary.readouterr`` method calls
+
-    which return a ``(out, err)`` tuple.  ``out`` and ``err`` will be
+    The captured output is made available via ``capfd.readouterr()`` method
-    ``bytes`` objects.
+    calls, which return a ``(out, err)`` namedtuple.
+    ``out`` and ``err`` will be ``byte`` objects.
     """
     _ensure_only_one_capture_fixture(request, "capfdbinary")
     if not hasattr(os, "dup"):
@@ -316,9 +326,9 @@ def _install_capture_fixture_on_item(request, capture_class):
     """
     request.node._capture_fixture = fixture = CaptureFixture(capture_class, request)
     capmanager = request.config.pluginmanager.getplugin("capturemanager")
-    # need to active this fixture right away in case it is being used by another fixture (setup phase)
+    # Need to active this fixture right away in case it is being used by another fixture (setup phase).
-    # if this fixture is being used only by a test function (call phase), then we wouldn't need this
+    # If this fixture is being used only by a test function (call phase), then we wouldn't need this
-    # activation, but it doesn't hurt
+    # activation, but it doesn't hurt.
     capmanager.activate_fixture(request.node)
     yield fixture
     fixture.close()
@@ -446,6 +456,9 @@ class MultiCapture(object):
         if err:
             self.err = Capture(2)
 
+    def __repr__(self):
+        return "<MultiCapture out=%r err=%r in_=%r>" % (self.out, self.err, self.in_)
+
     def start_capturing(self):
         if self.in_:
             self.in_.start()
@@ -593,7 +606,7 @@ class FDCapture(FDCaptureBinary):
     EMPTY_BUFFER = str()
 
     def snap(self):
-        res = FDCaptureBinary.snap(self)
+        res = super(FDCapture, self).snap()
         enc = getattr(self.tmpfile, "encoding", None)
         if enc and isinstance(res, bytes):
             res = six.text_type(res, enc, "replace")
@@ -696,11 +709,9 @@ def _colorama_workaround():
     first import of colorama while I/O capture is active, colorama will
     fail in various ways.
     """
-
+    if sys.platform.startswith("win32"):
-    if not sys.platform.startswith("win32"):
-        return
         try:
-        import colorama  # noqa
+            import colorama  # noqa: F401
         except ImportError:
             pass
 
@@ -723,11 +734,9 @@ def _readline_workaround():
 
     See https://github.com/pytest-dev/pytest/pull/1281
     """
-
+    if sys.platform.startswith("win32"):
-    if not sys.platform.startswith("win32"):
-        return
         try:
-        import readline  # noqa
+            import readline  # noqa: F401
         except ImportError:
             pass
 

testing/test_capture.py

@@ -566,7 +566,7 @@ class TestCaptureFixture(object):
         result.stdout.fnmatch_lines(
             [
                 "*test_hello*",
-                "*capsysbinary is only supported on python 3*",
+                "*capsysbinary is only supported on Python 3*",
                 "*1 error in*",
             ]
         )